Good Debug skills. I remember the 8000 Char limit. Well the good news is, we fixed that bug 4 years ago! It was Defect Id 191744 It was fixed from 7.6 onwards. If you have a support contract, you can upgrade to any of the newer versions and the problem is resolved.
 Hi  our current setup is the following version: vWorkspace Version 7.5.304.547 on Windows 2008R2 Standard. When a new user logs into the brokers via the HTTP link, they see the web portal with the logon textboxes, however when they input their credentials they are given the following error: error cannot connect to vworkspace connection broker. Please contact your system administrator. existing users can connect without issues. We have checked that the user's account is not locked.  I have checked the link, [URL] however we don't have additional farm. I've rebooted the connection brokers and checked the event logs without finding the problem.  
error cannot connect to vworkspace connection broker. Please contact your 
system administrator.