What account is the schedule (AT) service using?
If you using the local or system accounts for the service it may not have enough rights to run you script/uninstall.
The local/system accounts can't valiated by the domain controller so they will not be able to access network resources.
To verify it isn't an authority problem & to allow access to network resources, change the schedule service account to logon with a domain administrators account and restart the service.
Is the uninstallapplication 16 bit?
Cause unless 16bit apps have access to
the interactive desktop, i.e. /interactive, they most likely will not start as they are required run under Ntvdm.
Re-enter your AT command with /interactive and test.
Good luck, Mike.