ToME WikiLevel generation in Theme 1.2.0 (using ToME 2.3.4) is extremely slow, especially with Ironman rooms enabled - much, much slower than in ToME 2.3.4. Even for small levels, it can take over a minute (with 512 MB of RAM and a 1.6 GHz Core Solo processor), and that's just the first generation - with Ironman rooms, second and third attempts are often required for various reasons (could not place player, too many items, etc.).
By contrast, I have never on any occasion seen generic ToME level generation - with Ironman rooms and the works - take more than five seconds.
SigSegv: Have you tried the patches found here:
http://forum.t-o-m-e.net/viewtopic.php?t=13788
Specifically, the patch to generate.c.