i have compiled mozilla-firefox-1.5-r4 with gcc-4.0.2-r2 (my whole system is compiled with gcc 4 - i know it's not supported). Firefox crashes immediately when i access a flash site and it loades the flash plugin (netscape-flash-7.0.61): The program 'Gecko' received an X Window System error. This probably reflects a bug in the program. The error was 'BadMatch (invalid parameter attributes)'. (Details: serial 97 error_code 8 request_code 146 minor_code 3) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.) firefox-bin exited with non-zero status (1) Maybe its a problem with X11 too. I'm running the latest masked modular X11R7.
move old profile and let it recreate it. Re-open with emerge info if you want any further support