What means the error message: ”MAPI-Error: MAPI_E_NOT_ENOUGH_RESOURCES”?

We are not sure If the error means that the Hardware resources used by Outlook are exhausted or If the pst file is corrupt. 

First of all you should try to repair your Outlook profile(s) and pst file(s). Use OLfix for this.

If the error appears again you should close some other programs and try again.