mrlich | Problem with TalkPost

I am using Outlook Express and Firefox as my browser. When I get a response to one of my posts on LJ, I try to respond though the email (ie via the talkpost function) but ever since I started using FireFox I get an error that reads:

One or more errors occurred processing your request. Please go back, correct the necessary information, and submit your data again.

Comment not posted: POST required, or missing parameter.

Anyone know what's going on or how to fix it? Much thanks!