Sorry for the slow reply, I thought I had notifications from comments turned on, it seems they weren't :(
I'll look into it. This is a shader compilation error, so it should be easy enough to fix. Thank you for reporting!
Sadly, TAGAP 4 requires Windows 8.1 or later. I'm sorry about that :(
Thank you for your kind words! And double-thank you for reporting the bug, I'll see if I can hammer it out.