This is due to the conflict between ispLEVER Classic 1.5 with old installed ispLEVER version(e.g. ispLEVER 6.1). Users can try the below methods:
1. Uninstall and re-install the software ispLEVER Classic 1.5, make sure the user has the admin privileges.
2. If the first one does not work, try renaming the registry entry:
HKEY_LOCAL_MACHINE -> SOFTWARE -> Lattice Semiconductor Corporation -> ispLEVER -> 6.1 (install version) to HKEY_LOCAL_MACHINE -> SOFTWARE -> Lattice Semiconductor Corporation -> ispLEVER -> 6.1 old (install version), then try re-installing of the software.