If you are receiving MAPI Error 26 please refer to the following:
Here are the instructions from the article:
1. Quit all programs.
2. Rename the Mapi32.dll file in the C:\Windows\System32 folder to "Mapi32.old" (without quotation marks).
3. Locate the Fixmapi.exe file in the C:\Windows\System32 folder, and then double-click Fixmapi.exe to run the program.
4. Restart your computer.