Uninstalling ‘MetaFrame Presentation Server’ – Error 29501

While uninstalling ‘MetaFrame Presentation Server’ from a server which is in my farm, I got the following error message.
Error 29501. Setup has determined that Application Isolation Environments exist on this server.
Remove all of these before continuing with uninstallation.
My server’s address is enclosed in ‘an isolation environment definition’. I can’t guess what the problem is.
Can you?
Please help ASAP.

