The coin glitch is mutual, I have the same thing happening to me. But
check if there is free space for new level creation, and last software updates, blah blah blah that kinda junk. This is a DEVELOPMENT VERSION.
Try to get a Nightly Build
, they're probably going to fix the problem (or not, even make it worse)
Try to get SuperTux 0.5.0
.
There is also a chance that the download did not completed himself and got corrupted.
Else,
have no idea.