I have an Add Shared Resource script item in my installer:

Name: [PRODUCTNAME]
Share Type: STYPE_DISKTREE
Share Path: %_SB_INSTALLDIR%

For Server Name, I've tried "%COMPUTER_NAME%", "\\%COMPUTER_NAME%", and a blank field (NetShareAdd docs state that a NULL servername argument means the local machine). %COMPUTER_NAME% holds the result of GetSystemInformation(ComputerName).

In all of these cases, Add Shared Resource does nothing. I have stepped through in debug mode: No shared folder is created, %_SB_ERRORCODE% retains a blank value, nothing is logged to the Event Viewer. What's going on?

I am an Administrator on this machine. I'm running XP.