I have also had this segmentation fault problem on Ubuntu Jaunty and it was a real showstopper. Even building the latest Wine from source didn't help. I have followed the instructions to generate a stack trace, but gdb seems unable to read the core file, and just tells me that no backtrace is available. I finally figured out that this started happening when the kernel was upgraded to 2.6.28-15-generic. I rebooted back into kernel 2.6.28-14-generic and I can finally run Wine again. I hope this work-around helps anyone with a similar problem.
