URGENT: Problem uploading attachments - Loops forever.

[cybercreative]

I have installed Roundcube under IIS7 on Windows 2008 with Hmailserver.

All works fine except the attachment upload.

I can browse the hard drive and select a file to upload but when I click upload the spinning circle shows and says uploading file. It just stays there continuously looping. No errors are shown in logs because it never throws an error. Just continues to loop. It affects all file types and file sizes.

I can receive and forward emails with attachments and the attachments are stored successfully in the temporary directory.

In the config it has $rcmail_config['temp_dir'] = 'temp/'; and the directory has write permission. The same setup for $rcmail_config['log_dir'] = 'logs/'; and items are recorded in the logs such as invalid logins.

Other PHP sites on our server have no problem uploading files so I don't think its specific to PHP and all relevant PHP upload settings are activated and correct.

Any ideas or help would be appreciated.