Posting with different browsers?

[Hueij]

When I try to post in IE everything works fine but when i use Opera (my favourite) I get the following message:

No thread specified. If you followed a valid link, please notify the webmaster

Anyone knows what's going on?

Edit: I just found out that I can't add my birthday in my profile:

There is already a member with that email address, and the administrator has required that all users must have unique email addresses. If you already have a username and have forgotten your password, please click here.

[Urban Ranger]

Are there some Opera settings different from IE? I used both IE and Mozilla with no problems. Okay, not no problems, but no problems with posting plain messages. Mozilla has trouble with attaching files.