Try registering the following DLL files:
3iicapibase.dll
3iicapicore.dll
3iicapidrawing.dll
3iicapiironcadapp.dll
ModelingHelper.dll
To register the DLL files:
Close IronCAD
Go to \Program Files\IronCAD\9.0\bin
Double-click the file 3iicapibase.dll, in the Open With dialog, click Browse, then select C:\WINDOWS\system32\regsvr32.exe to open the file with. Open, OK.
Then just double-click each of the remaining files listed above.