I have been trying to accept the answer for this question for 4 hours now.
I keep receiving the message 'you can accept the answer in 5 minutes'.
Is this something I should worry about?
Or just trying later on might works?
Digging through the traffic logs, I see exactly two attempts to accept that answer coming from your IPs.
The first, at 2012-10-14 10:53:06.573, would have fallen in the "you must wait 5 minutes to accept" window and been correctly rejected.
The second, at 2012-10-16 10:17:51.477, is the one that actually accepted the answer.
Since no other votes got to our logs, I'm forced to guess a little bit about what happened here but I've got an idea...
I noticed that you were trying to vote from an iOS 6 device, and the symptoms match a bad browser cache or proxy (whenever you're voting your sending a
POST request, which should never be cached; but if it were, the "wait 5 minutes" message would always be returned and the request would never be sent). It just so happens that there is a known bug in Safari on iOS 6 related to
POST and caching, and I strongly suspect that you're falling victim to it (that clearing Safari's cache ultimately fixed it is another point of evidence).
For now all I can advise is that you don't vote using an iOS 6 device, and hope Apple patches this quickly (I'm a little shocked this hasn't already been patched honestly, that's a massive bug).
With all the tentatives Willie and I did, a possible resolution might be the following.
Do a 'Clear all data and cookie' in your browser. Restart your browser. Relog into mathSE and try to accept the question.
If (1) fails, ask someone who can to make a small edit to the answer, so that the vote lock will be void. Then try (1) again.
How this bug appeared:
Up vote the answer, downvote it right, then up vote right away. Your vote should be locked now.
Try to accept the answer, you should received 'you can only acceot in 5 minutes'.