16 bpp is ok, 32 bpp is not supported by the tdfx server, accordingly to the error message. The XFree-3 server (SVGA) supports this depth. The card is a Voodoo 3.
If you're talking about a XFree86 4.0 driver, bug fixed.
Created attachment 2676 [details] XFree log
Nope. Same error, see the attachement of /var/log/XFree.0.log. Stelian
The log that you supplied is telling you that the tdfx driver does not support 32 bit mode. This is not a bug, it is just not supported. The error is not an XFree86 error, but a configuration error. Configure XFree86 in 16 bit mode for the best support. Alternatively, If you try using the XFree86-4.0.3-5 from rawhide, it may or may not add the support you need to use the mode you'd like.