The FAQ for the Windows Installer says about MS Sans Serif:

#Question:
I installed Gimp 2.0 on Windows 9x/ME or NT 4, and I'm getting a lot
of messages saying ** (gimp-2.0.exe:4294830849): WARNING **: Couldn't
load font "MS Sans Serif 8" falling back to "Sans 8". What should I do?
#Answer:
You have two options:
* Go to Control Panel->Display properties->Apperance tab, and set all
fonts to Tahoma (or any other TrueType font).
* Uninstall GTK+ 2.2.4, then re-install it without the GTK-Wimp
component."
http://www2.arnes.si/~sopjsimo/gimp/faq.html

Hope this will help you install The GIMP 2.0 without problems.

Greetings,

Martijn
http://gimp.pagina.nl