When attempting to run your program, there is a special case that will cause you to receive a runtime error message of "CoCreate Instance failed". This case involves running on a Microsoft Vista or Windows 2008 machine that previously (or currently) had ACUCOBOL-GT Version 8.0 installed on that machine.
This error is due to a combination of versions 8.0 and 8.1 using different CLSIDs (a unique identifier) for AcuToNet.dll, and Microsoft's more restrictive version control methods for side by side DLLs.
To correct this situation you need to use the ACUCOBOL-GT utility RegAsm20Acu.exe to register the version 8.1 AcuToNet.dll. Do this by performing the following steps:
regasm20acu /register /codebase AcuToNet.dll