I'm new here but figured I should put my .02 for this one... We're having the same issue with a client of ours. He's got an ATT S2 (Skyrocket) and I'm using my TMO S2 with the same error message "this document could not be opened". For sure its only related to the S2's running 2.3.6 as a coworker has a Nexus S running ICS and the attachment opens up without any problems.
Below is what I've done so far:
- Setup on other android devices has worked fine(both with native apps and
with downloads ie; touchdown, documents to go, etc)
- Setup on iOS device worked with no issues
- Checked moblie mailbox policies to make sure attachment viewing was
enabled and that no settings there might be responsible for the issue
- Other exchange setups on the Galaxy SII do not have problems withoffice
attachments and mail securitysetting in mail configuration have been checked. Only possible cause would be that they use Google's email archiving service though other phones don't have issues opening attachments.
Hopefully ICS will fix it!