I logged into your account and left feedback successfully, in Firefox, with no errors. Let me know if you'd like any of the comments changed.
Here are the steps I followed:
1. I clicked this link:
http://www.pentaxforums.com/forums/f...v-filters.html
2. I filled out every field the form.
3. I hit submit, and voila!
I really don't see where the error you're reporting was coming from. I wasn't able to replicate it for either you or carlb, so I can only conclude that either you were clicking the wrong link to leave feedback, or the popup was leading you to a page other than what I linked above.