The following threads have at least one person getting the same problem as you for at least the past few months. And, yes, I was just picking a few threads out, I'm sure there are more (threads 1 & 6 state the problem as its own topic):
Have you tried checking every day if you can vote that day?
I can't vote in the first 3 days of the week, but I can somewhere at the last days of the week..
This thread is closed to new posts.
However, you are welcome to reference it
from a new thread; link this with the html
<a href="/bboard/q-and-a-fetch-msg.tcl?msg_id=001oB3">BMV: problem</a>