Using The GIMP 2.0-pre2 (GTK+ 2.2.4-2) from Jernej Simoncic's page. I
encounter such behaviour: 1. open The GIMP; 2. select the text-tool; 3.
open its properties; 4. select the font selection dialog (this Aa icon); 5.
scroll down to see other fonts; 6. crash

I managed to gather some debug information. The GIMP crashes immediately
but if you open a large image then it closes itself a little bit longer
allowing to make at least a screenshot of the messages. Here they go:

** (gimp-1.3.exe:3332): WARNING **: [Invalid UTF-8] Unable to open font
file C:\WINDOWS\fonts\Sp#ywaj.ttf for font Sp##ywaj 16, falling back to
C:\WINDOWS\fonts\webdings.ttf

** (gimp-1.3.exe:3332): WARNING **: Unable to load unicode charmap from
file C:\WINDOWS\fonts\webdings.ttf, exiting

First of all, Poland uses Central European character sets such as
ISO-8859-2 or CP-1250. It is Latin but with some enhancement sings. A hash
# represents a corrupted sign which was in the place of a polish special
sign. So the bug is probably caused by this.
Moreover, I decided to delete all fonts with polish signs from
C:\WINDOWS\FONTS\ since The GIMP is just so cool BUT still I get exactly
the same message concerning Sp#ywaj.ttf which I deleted successfully.

About the second warning: there are some fonts which do not have any
alphabetical characters (these are used with the Windows GUI, represent
musical notes or glyphs, etc.) so they should be handled without crashing.

Still I don't actually know which of the two reasons matters most. Good luck.

Regards,
Lucas 'kSh' Langa