Today I tried upgrading Office Mobile in my phone to the new Microsoft Office Mobile 6.1. No matter what I tried I was presented with this very informative error message:
Installer asked me: "Error?". Since I didn't see any reason for this very well explained error I answered "No" and installation failed. 3 times. Then I gave up and pressed "Yes" and all went smoothly from there and newly installed office even seems to be working fine.