The Flip is This?

[chablah]

Notice I am using this app to post this, this picture uploaded fine, and all of the file chunks succeeded before the failure message. If I keep fiddling with it, I get a flash that reads "You cannot modify your profile."

 

[Xyro]

I believe this is a known problem with both tapatalk and the AF app (a branded copy of tapatalk), to which there's no current solution or workaround. The only way to set your avatar and profile picture is to browse the forum directly:
http://androidforums.com/profile.php?do=editavatar
http://androidforums.com/profile.php?do=editprofilepic