Question about reading Registry

I am trying to check for the existance of a MSDE install. The registry key I am checking for exist on the computer, but the logic always jumps to the installMSDE label. What am I doing wrong?

ClearErrors
ReadRegStr $0 HKLM "SOFTWARE\Microsoft\Microsoft SQL Server\RSG\MSSQLServer\CurrentVersion\CurrentVersion" ""
IfErrors installMSDE

You may need to jump if there are no errors...

IfErrors InstallMSDE NoInstallMSDE
InstallMSDE:

NoInstallMSDE:

-Stu