Older releases of fvwm1 and fvwm2 and (for the brave) the latest alpha and beta releases, as well as unofficial patches, can be found here.
Please keep in mind that the Beta code can potentially become unstable or buggy at any time, so USE AT YOUR OWN RISK. Of course you may find bugs in "Official" versions also.
If you find any bugs, you can enter them into the FVWM Bug Tracking System. If possible, please try searching to see if someone else has already reported this bug. If you have more or better information, feel free to add a note!
If you just have a question, be sure to read our Documentation first, then you might want to try our Mailing List.
When asking for help, of course always remember to provide the release number of fvwm, your operating system, and any other information you think might be pertinent.