Didn't you check $@ to see what error eval found? You forgot about quoting.

for ($str) {
   s/\\/\\\\/g;
   s/'/\\'/g;
   s/\(/['/g;
   s/\)/']/g;
   s/,/','/g;
}
[download]

Update: Bah, that's buggy, but you get the idea. I'm not gonna fix it, cause it's more effort making this work with eval EXPR than developing a safer solution (i.e. one that doesn't use eval EXPR).