Are you just trying to plot all three series? There should be no problem, except that it appears your column names in tsv file include the "+" and "-" character which I'm not sure is allowed:
Unixtime stream +Avgstream -Avgstream
1351805809 5594 5489 6379
1351865010 5468 5489 6379
1351868732 5479 5489 6379
1351875915 5504 5489 6379
1351883184 7177 5489 6379
1351890345 5481 5489 6379
...
I replaced your column names (and tsv decoding) with:
data = [
{Unixtime:1351805809, stream: 5594, plusavg:5489, lessavg:6379},
{Unixtime:1351865010, stream: 5468, plusavg:5489, lessavg:6379},
{Unixtime:1351868732, stream: 5479, plusavg:5489, lessavg:6379},
{Unixtime:1351875915, stream: 5504, plusavg:5489, lessavg:6379},
{Unixtime:1351883184, stream: 7177, plusavg:5489, lessavg:6379}
];
And I get three lines in the chart:
Is that sort of what you are trying to do? See here.