well well...

is the addprinterconnection also with lower case?
does it work if you use @lserver with addprinterconnection AND setdefaultprinter?

I think what is going on in here is that the program cares about case even though windows doesn't.
windows still stores the case in the default printer info and thus, if the case for the added printer and default printer are different, the program gets confused.

continuing on this logic, vbscript then only works as long as the printer is also added lowercase. if you add it with kix and have capitals in it, then it should fail. or, as Shane suggested, using only lowercase default printer.
if the printername (and the servername) contain uppercase characters in both places:
a) HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Devices
b) HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows,Device-value

and the program still doesn't work right, then the program only accepts lowercase servername, which is odd and shall be an issue with the program itself.
if it works, then it's just matter of the program caring too much in windows standards but I might not call it a bug in that cause. maybe a odd feature instead.
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