Currently if the OCI.DLL can not be loaded due to missing/incomplete Oracle Client installation an rather end-user unfriendly general exception dialog is shown:
e.g. "OCI8: Cannot allocate OCI handle.
Program: SQLTools 1.4.2 RC3 (for trouble-shooting)
Platform: MS Windows Server 2003 family Enterprise, Service Pack 2 (Build 3790)
It would be nice if this would be shown as an specific exception that explains that the OCI.DLL could not be loaded, probably due to an incomplete Oracle Client setup (e.g. usually just copying the OCI.DLL somewhere without adding the Oracle Client BIN directory to the path leads to this error)