Sort for Czech characters PHP - issue in compare function

Question

I'm making sorted sorting of Czech (and other) characters. I wrote a compare function but there is a problem with strstr:

Warning: strstr() [function.strstr]: needle is not a string or an integer in ...

And second problem is that it doesn't compare it correctly. I checked the manual of usort and some examples and think it should be ok, but something is wrong. I also check $a->getJmenoSouboru() and $b->getJmenoSouboru() on string and it is really string. So I don't understand to that warning.

     class Soubor {
            private  $jmenoSouboru;
            private  $datumPosledniZmeny;

            /**
             * @param mixed $datumPosledniZmeny
             */
            public function setDatumPosledniZmeny($datumPosledniZmeny)
            {
                $this->datumPosledniZmeny = $datumPosledniZmeny;
            }

            /**
             * @return mixed
             */
            public function getDatumPosledniZmeny()
            {
                return $this->datumPosledniZmeny;
            }

            /**
             * @param mixed $jmenoSouboru
             */
            public function setJmenoSouboru($jmenoSouboru)
            {
                $this->jmenoSouboru = $jmenoSouboru;
            }

            /**
             * @return mixed
             */
            public function getJmenoSouboru()
            {
                return $this->jmenoSouboru;
            }

            public function __construct() {
                // allocate your stuff
            }

            public static function withParameters($jmeno, $datum) {
                $instance = new self();
                $instance->jmenoSouboru = $jmeno;
                $instance->datumPosledniZmeny = $datum;
                return $instance;
            }

    }

$pole = array();
$items = array('zmatek', 'řeřicha', 'rumcajz', 'ahojda', 'čeněk', 'ájina', 'žampion');

$i = 0;
foreach ($items as $value) {
    $i++;
    $soubor = Soubor::withParameters($value, $i.".4.2014");
    $pole[] = $soubor;
}


    function sort_by_name_ascii($a, $b) {
        static $translations;
        //z důvodů úspory výkonu je pole $translations vytvářeno pouze při prvním volání
        if(!$translations) {
            if($bool = is_file('translations.txt')) {
                echo("bool:".$bool);
                $translations = parse_ini_file('translations.txt');

            }
        }
        echo(is_string($a->getJmenoSouboru()). " ".$b->getJmenoSouboru()."<br />");

        $A = strstr($a->getJmenoSouboru(), $translations);
        $B = strstr($b->getJmenoSouboru(), $translations);
        return strnatcasecmp($A, $B);
    }

    usort($pole, "sort_by_name_ascii");
    echo "<br /> Sorted array<br />";
foreach($pole as $k => $prvek) {
    echo($prvek->getJmenoSouboru());
    echo(" ".$prvek->getDatumPosledniZmeny());
    echo("<br />");
}

translations.txt looks like this:

; global transliteration
[default]
À = "A"
Á = "A"
 = "A"
à = "A"
Ä = "Ae"
Å = "A"
Æ = "A"
Ā = "A"
Ą = "A"
Ă = "A"
Ç = "C"
Ć = "C"
Č = "CZZ"
Ĉ = "C"
Ċ = "C"
Ď = "DZZ"
Đ = "D"
È = "E"
É = "E"
Ê = "E"
Ë = "E"
Ē = "E"
Ę = "E"
Ě = "E"
Ĕ = "E"
Ė = "E"
Ĝ = "G"
Ğ = "G"
Ġ = "G"
Ģ = "G"
Ĥ = "H"
Ħ = "H"
Ì = "I"
Í = "I"
Î = "I"
Ï = "I"
Ī = "I"
Ĩ = "I"
Ĭ = "I"
Į = "I"
İ = "I"
IJ = "IJ"
Ĵ = "J"
Ķ = "K"
Ľ = "K"
Ĺ = "K"
Ļ = "K"
Ŀ = "K"
Ł = "L"
Ñ = "N"
Ń = "N"
Ň = "NZZ"
Ņ = "N"
Ŋ = "N"
Ò = "O"
Ó = "O"
Ô = "O"
Õ = "O"
Ö = "Oe"
Ø = "O"
Ō = "O"
Ő = "O"
Ŏ = "O"
Π= "OE"
Ŕ = "R"
Ř = "RZZ"
Ŗ = "R"
Ś = "S"
Ş = "S"
Ŝ = "S"
Ș = "S"
Š = "SZZ"
Ť = "TZZ"
Ţ = "T"
Ŧ = "T"
Ț = "T"
Ù = "U"
Ú = "U"
Û = "U"
Ü = "Ue"
Ū = "U"
Ů = "UZZ"
Ű = "U"
Ŭ = "U"
Ũ = "U"
Ų = "U"
Ŵ = "W"
Ŷ = "Y"
Ÿ = "Y"
Ý = "Y"
Ź = "Z"
Ż = "Z"
Ž = "ZZZ"
à = "a"
á = "a"
â = "a"
ã = "a"
ä = "ae"
ā = "a"
ą = "a"
ă = "a"
å = "a"
æ = "ae"
ç = "c"
ć = "c"
č = "czz"
ĉ = "c"
ċ = "c"
ď = "dzz"
đ = "d"
è = "e"
é = "e"
ê = "e"
ë = "e"
ē = "e"
ę = "e"
ě = "e"
ĕ = "e"
ė = "e"
ƒ = "f"
ĝ = "g"
ğ = "g"
ġ = "g"
ģ = "g"
ĥ = "h"
ħ = "h"
ì = "i"
í = "i"
î = "i"
ï = "i"
ī = "i"
ĩ = "i"
ĭ = "i"
į = "i"
ı = "i"
ij = "ij"
ĵ = "j"
ķ = "k"
ĸ = "k"
ł = "l"
ľ = "l"
ĺ = "l"
ļ = "l"
ŀ = "l"
ñ = "n"
ń = "n"
ň = "nzz"
ņ = "n"
ʼn = "n"
ŋ = "n"
ò = "o"
ó = "o"
ô = "o"
õ = "o"
ö = "oe"
ø = "o"
ō = "o"
ő = "o"
ŏ = "o"
œ = "oe"
ŕ = "r"
ř = "rzz"
ŗ = "r"
ś = "s"
š = "szz"
ş = "s"
ť = "tzz"
ţ = "t"
ù = "u"
ú = "u"
û = "u"
ü = "ue"
ū = "u"
ů = "u"
ű = "u"
ŭ = "u"
ũ = "u"
ų = "u"
ŵ = "w"
ÿ = "y"
ý = "y"
ŷ = "y"
ż = "z"
ź = "z"
ž = "zzz"
ß = "ss"
ſ = "ss"
Α = "A"
Ά = "A"
Ἀ = "A"
Ἁ = "A"
Ἂ = "A"
Ἃ = "A"
Ἄ = "A"
Ἅ = "A"
Ἆ = "A"
Ἇ = "A"
ᾈ = "A"
ᾉ = "A"
ᾊ = "A"
ᾋ = "A"
ᾌ = "A"
ᾍ = "A"
ᾎ = "A"
ᾏ = "A"
Ᾰ = "A"
Ᾱ = "A"
Ὰ = "A"
Ά = "A"
ᾼ = "A"
Β = "B"
Γ = "G"
Δ = "D"
Ε = "E"
Έ = "E"
Ἐ = "E"
Ἑ = "E"
Ἒ = "E"
Ἓ = "E"
Ἔ = "E"
Ἕ = "E"
Έ = "E"
Ὲ = "E"
Ζ = "Z"
Η = "I"
Ή = "I"
Ἠ = "I"
Ἡ = "I"
Ἢ = "I"
Ἣ = "I"
Ἤ = "I"
Ἥ = "I"
Ἦ = "I"
Ἧ = "I"
ᾘ = "I"
ᾙ = "I"
ᾚ = "I"
ᾛ = "I"
ᾜ = "I"
ᾝ = "I"
ᾞ = "I"
ᾟ = "I"
Ὴ = "I"
Ή = "I"
ῌ = "I"
Θ = "TH"
Ι = "I"
Ί = "I"
Ϊ = "I"
Ἰ = "I"
Ἱ = "I"
Ἲ = "I"
Ἳ = "I"
Ἴ = "I"
Ἵ = "I"
Ἶ = "I"
Ἷ = "I"
Ῐ = "I"
Ῑ = "I"
Ὶ = "I"
Ί = "I"
Κ = "K"
Λ = "L"
Μ = "M"
Ν = "N"
Ξ = "KS"
Ο = "O"
Ό = "O"
Ὀ = "O"
Ὁ = "O"
Ὂ = "O"
Ὃ = "O"
Ὄ = "O"
Ὅ = "O"
Ὸ = "O"
Ό = "O"
Π = "P"
Ρ = "R"
Ῥ = "R"
Σ = "S"
Τ = "T"
Υ = "Y"
Ύ = "Y"
Ϋ = "Y"
Ὑ = "Y"
Ὓ = "Y"
Ὕ = "Y"
Ὗ = "Y"
Ῠ = "Y"
Ῡ = "Y"
Ὺ = "Y"
Ύ = "Y"
Φ = "F"
Χ = "X"
Ψ = "PS"
Ω = "O"
Ώ = "O"
Ὠ = "O"
Ὡ = "O"
Ὢ = "O"
Ὣ = "O"
Ὤ = "O"
Ὥ = "O"
Ὦ = "O"
Ὧ = "O"
ᾨ = "O"
ᾩ = "O"
ᾪ = "O"
ᾫ = "O"
ᾬ = "O"
ᾭ = "O"
ᾮ = "O"
ᾯ = "O"
Ὼ = "O"
Ώ = "O"
ῼ = "O"
α = "a"
ά = "a"
ἀ = "a"
ἁ = "a"
ἂ = "a"
ἃ = "a"
ἄ = "a"
ἅ = "a"
ἆ = "a"
ἇ = "a"
ᾀ = "a"
ᾁ = "a"
ᾂ = "a"
ᾃ = "a"
ᾄ = "a"
ᾅ = "a"
ᾆ = "a"
ᾇ = "a"
ὰ = "a"
ά = "a"
ᾰ = "a"
ᾱ = "a"
ᾲ = "a"
ᾳ = "a"
ᾴ = "a"
ᾶ = "a"
ᾷ = "a"
β = "b"
γ = "g"
δ = "d"
ε = "e"
έ = "e"
ἐ = "e"
ἑ = "e"
ἒ = "e"
ἓ = "e"
ἔ = "e"
ἕ = "e"
ὲ = "e"
έ = "e"
ζ = "z"
η = "i"
ή = "i"
ἠ = "i"
ἡ = "i"
ἢ = "i"
ἣ = "i"
ἤ = "i"
ἥ = "i"
ἦ = "i"
ἧ = "i"
ᾐ = "i"
ᾑ = "i"
ᾒ = "i"
ᾓ = "i"
ᾔ = "i"
ᾕ = "i"
ᾖ = "i"
ᾗ = "i"
ὴ = "i"
ή = "i"
ῂ = "i"
ῃ = "i"
ῄ = "i"
ῆ = "i"
ῇ = "i"
θ = "th"
ι = "i"
ί = "i"
ϊ = "i"
ΐ = "i"
ἰ = "i"
ἱ = "i"
ἲ = "i"
ἳ = "i"
ἴ = "i"
ἵ = "i"
ἶ = "i"
ἷ = "i"
ὶ = "i"
ί = "i"
ῐ = "i"
ῑ = "i"
ῒ = "i"
ΐ = "i"
ῖ = "i"
ῗ = "i"
κ = "k"
λ = "l"
μ = "m"
ν = "n"
ξ = "ks"
ο = "o"
ό = "o"
ὀ = "o"
ὁ = "o"
ὂ = "o"
ὃ = "o"
ὄ = "o"
ὅ = "o"
ὸ = "o"
ό = "o"
π = "p"
ρ = "r"
ῤ = "r"
ῥ = "r"
σ = "s"
ς = "s"
τ = "t"
υ = "y"
ύ = "y"
ϋ = "y"
ΰ = "y"
ὐ = "y"
ὑ = "y"
ὒ = "y"
ὓ = "y"
ὔ = "y"
ὕ = "y"
ὖ = "y"
ὗ = "y"
ὺ = "y"
ύ = "y"
ῠ = "y"
ῡ = "y"
ῢ = "y"
ΰ = "y"
ῦ = "y"
ῧ = "y"
φ = "f"
χ = "x"
ψ = "ps"
ω = "o"
ώ = "o"
ὠ = "o"
ὡ = "o"
ὢ = "o"
ὣ = "o"
ὤ = "o"
ὥ = "o"
ὦ = "o"
ὧ = "o"
ᾠ = "o"
ᾡ = "o"
ᾢ = "o"
ᾣ = "o"
ᾤ = "o"
ᾥ = "o"
ᾦ = "o"
ᾧ = "o"
ὼ = "o"
ώ = "o"
ῲ = "o"
ῳ = "o"
ῴ = "o"
ῶ = "o"
ῷ = "o"
¨ = ""
΅ = ""
᾿ = ""
῾ = ""
῍ = ""
῝ = ""
῎ = ""
῞ = ""
῏ = ""
῟ = ""
῀ = ""
῁ = ""
΄ = ""
΅ = ""
` = ""
῭ = ""
ͺ = ""
᾽ = ""
А = "A"
Б = "B"
В = "V"
Г = "G"
Д = "D"
Е = "E"
Ё = "E"
Ж = "ZH"
З = "Z"
И = "I"
Й = "I"
К = "K"
Л = "L"
М = "M"
Н = "N"
О = "O"
П = "P"
Р = "R"
С = "S"
Т = "T"
У = "U"
Ф = "F"
Х = "KH"
Ц = "TS"
Ч = "CH"
Ш = "SH"
Щ = "SHCH"
Ы = "Y"
Э = "E"
Ю = "YU"
Я = "YA"
а = "A"
б = "B"
в = "V"
г = "G"
д = "D"
е = "E"
ё = "E"
ж = "ZH"
з = "Z"
и = "I"
й = "I"
к = "K"
л = "L"
м = "M"
н = "N"
о = "O"
п = "P"
р = "R"
с = "S"
т = "T"
у = "U"
ф = "F"
х = "KH"
ц = "TS"
ч = "CH"
ш = "SH"
щ = "SHCH"
ы = "Y"
э = "E"
ю = "YU"
я = "YA"
Ъ = ""
ъ = ""
Ь = ""
ь = ""

ð = "d"
Ð = "D"
þ = "th"
Þ = "TH"

Answer 1

Instead of strstr must be strtr :/
sh*t just happens. So if anyone needs it, works fine ;)