If you're using the same text from the same file over and over again - you'd better read it into a string before the loop starts and then use the string over and over again:
string str = System.IO.File.ReadAllText("c:\docs\xyz.log");
...
// now use str in the loop
start:
...
Comment:
It's a bad practice to write so many commands on the same line, when you'll get an error you wouldn't know where it's coming from.