firefox 4 beta ... not retaining setup data

on a typical day, i'll use portable firefox 4 beta at work and update extensions as necessary.

later, i'll be at home and fire up firefox 4 beta only to discover that i have to update the same extensions all over again.

apparently, firefox 4 beta isn't retaining setup data but i haven't a clue about how to fix it.

i have firefox 3.6.13 portable on the same drive but rarely use it. might it be that the firefoxes are conflicting/confused about where setup data should be stored?

thanks for any help.

regards, ..