Problem in uninstallation:LifeCycleDesigner7.1



I have Adobe Live Cycle Designer 7.1 installed in system. Now i need to install Adobe Live Cycle Designer 8. Before that i want to uninstall 7.1. But i could not uninstall 7.1 (through ADD OR REMOVE PROGRAMS), it is giving error message

"Failed to open /parse setup script. Please check if the script file 'setup/NwSapSetp.xsc' exists"

But 'setup/NwSapSetp.xsc' file is present in the system in location 'C:\Program Files\SAP\SapSeup\setup'.

If i open C:\Program Files\SAP\SapSeup\setup\NwSapSetp.exe it is giving same error.

I tried to uninstall using string

"C:\Program Files\SAP\SAPsetup\setup\NwSapsetup.exe" /product:"ALD" /uninstall /noRestart"

But it is giving same error.

Can any one help in this....