Maybe I'm missing something, but here is my thinking.

1. Framework 2 service pack 1, which is what your redistributable is, requires XP Service Pack 2.
2. Line 80 used to be: If %SERVICEPACKNUMBER% Does Not Equal 2 Then ... Don't Install the framework.
3. I'm on Service Pack 3, I want it to install for any service pack 2 and above, thus If %SERVICEPACKNUMBER% Less Than 2 Then ... Don't Install the framework.

Am I all wet?