Below is straight from the Inter-Tel knowledge base. It seemed like it happened to me when I got a new computer and re-installed all the DB softwares. It's an old knowledge base answer, but it worked for me within the past year. If that don't work, not sure. Good luck.
Getting msjet35.dll Error when opening the Session Manager
Question
When opening session manager for database programming you get an msjet35.dll error and session manager will not run.
Answer
You will need the latest version of Microsoft Jet 3.5. It can be downloaded here:
https://support.microsoft.com/kb/172733
