Did you run the tool as administrator? I had that issue once before and it did the trick.
I believe you might have downloaded the old version of this utility found on
There is an updated version of this tool at:
The previous version posted for IPAM 4.1 might not work correctly with IPAM 4.2 and 4.3. This newer version should work with 4.2 and above.
Note #1 please right click on the AddIP exe and "Run as Administrator"
Note #2 Please use Orion Administrator account with IPAM Admin rights (there is a known issue with trying to use Windows AD credentials that don't seem to let this tool work correctly.)