os X crashes when uploading images - parental controls?

hey world

we've had this issue for a while now where our imac crashes when my daughter attempts to upload an image to her tumblr page.

this isn't just a browser crash - its one of those doozys where the whole screen goes grey and we get the message asking us to shut the computer down by holding the power button etc etc.

we tried resetting the browser (firefox initially), trashed the prefs and disabled all addons. still it crashes on upload. we tried chrome, still it crashes.

the tricky thing is, when we repeated the steps under my login (admin), it all works fine.

after much testing we have narrowed this down to the fact that my daughters account has parental controls active.

the controls are set to limit login times, and for a maximum of 1 hour on school nights. there are no limitations to the system or firewalls, just the time limits.

when I deactivate parental controls she can post to tumblr just fine. as soon as I switch the controls back on, bam! it crashes.

there is a workaround for this - we discovered that safari works just fine with parental controls in place.

but we'd really rather use firefox. and surely we should be able to..?

i thought I'd post our problem to see if anyone else has experienced this when using the parental controls settings. I'm wondering if upgrading to lion will resolve this problem - so if anyone has done this and can advise if it will work, please let me know.

our system is as follows:

2.16ghz intel core 2 duo white imac

2gb 667 mhz ddr2 SDRAM

OS X 10.5.8

thank you!