I am experiencing a similar problem with the Facebook App... My device is a Palm Pre with webOS 1.4.5 and Facebook v1.5.62... Starting this morning, when opening the Facebook App I received a message stating "Communications error. An error occurred communicating with the server." and it gave me the option to "Retry" (which repeatedly generated the same Communications Error message) or "Dismiss" which would initially open the App, but without functionality & with a news feed that wouldn't refresh.
I then came to this forum and found this thread... The first suggestion that I attempted was to go into my Facebook App account preferences and sign out & back into my account. I was unable to successfully sign out of my account from my Pre - when I tried to sign out of the account I received a message saying "AcctMgr_Authentication_Bad_Request".
I then got on my desktop computer to sign in to my Facebook account and take a better look at my account from a computer. I went to my Account Settings/Apps page and noticed that the Facebook for HP webOS App has mysteriously disappeared and is no longer showing in my list of authorized apps. I also noticed that mobile uploads of 2 photos that I posted to Facebook from my Pre last Friday were no longer showing on my timeline (Actually all of my Mobile Uploads are missing - when I go to my Photos section it shows a Mobile Uploads folder with 9 photos, but when I open the folder there are no pictures there).
So the disappearance of the Facebook for HP webOS authorization has obviously created the issue with the App's integration between my Facebook account and my Pre.
I next went back to my Pre and uninstalled and reinstalled the Facebook App, thinking that the new installation & sign on would create a new authorization script for my account. Unfortunately that was not the case. The App did reinstall successfully, however when I open the App and get the initial Sign In page I am unable to sign in to my account and am back to getting the "AcctMgr_Authentication_Bad_Request" message that I had received earlier.
Does anyone have a suggestion as to how this issue can be resolved?