Unable to POST to Twitter or Wordpress or Facebook

I am running Ubuntu 10.4 LTS and Firefox 3.6.x

I am unable to post anything to twitter through twitter.com. I have used other services such as brizzly and it works fine there. Also I tried through CURL and I am able to update my status on twitter through that as well. However, from the twitter.com website it just doesn't work. It times out and says that there was some technical problem. I have no such problems on Windows.

I read a similar question on Launchpad where it says to set my Locale to en-us and I did that as well. I set the order to En-US as the first one with En as the second priority and I have applied it system-wide and rebooted. However even that didn't work.

I am having a similar problem posting to my hosted wordpress blog. Whenever I post, it keep loading and finally nothing happens and it sends me back the php file. However, the php parser on my server is fine as I can post to it from all other Windows systems. Only my linux box doesn't work. I am suspecting some issue with the headers, but will be great if you can help me trace and find the cause of the problem. Even Facebook doesn't let me post comments. I suspect there is some problem with all PHP POST requests as typically they are the ones that are failing.

Also, launchpad doesn't login from Linux, so if you need any traces or want me to check something please let me know as I will have to boot into Linux and check and come back to Windows to post it.

Thanks,
Prashanth