What does the error message say?
In the error box, it should say "To view error details... click here
". Then you'll see something like
AppName: winamp.exe AppVer: 22.214.171.124 ModName: *******.dll
ModVer: *.*.*.* Offset: ******
If so, please post them.
If it's gen_ff.dll
that crashes, try deleting studio.xnf
while Winamp is closed (that file is stored in your Winamp folder, default C:\Program Files\Winamp
No luck? Try a clean install
Be sure you got the latest version of Winamp installed (i.e. 5.08).
Still no luck? Please provide full system specs
. Include a HijackThis log