I give up (for now).
Crashed 4 times in succession (-safe-mode). Last try was with (most) everything else closed & still crashed.
Perhaps I need to reboot (memory fragmented?), but not in a position to.
Still with most everything closed down (including FF), switched to another User (Windows), & did some stuff.
Logged out of that user, came back to current user, fired up FF, only the one Window, & the clip played to the end.
Opened a dozen or so tabs (about:blank), & then finally alt+home (not, does not work in FF, so clicked the "house"), then closed the ro.me tab.
At that point, FF went not responding. I let it sit - a LONG time, never did get it back, eventually killed it.
Looks like there are existing bugs on ROME,
https://bugzilla.mozilla.org/buglist.cg ... _id=267495.
To note: all my crashes & associated bug reports during this time have been (other then perhaps my comments) worthless, of the "...stackwalk.sh returned no header lines for reportid: 254551569; No thread was identified as the cause of the crash; No signature could be created..." ilk.
Win7 x86, 4GB ram, -safe-mode, or if with NoScript, v2.1.0.4rc10, SeaMonkey 2.1rc1, FF 4.0.1, FF 5 & 6 (20110514 builds).
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.19) Gecko/20110420 SeaMonkey/2.0.14 Pinball NoScript FlashGot AdblockPlus
Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20110511 Firefox/4.0.1 SeaMonkey/2.1