Not sure why that does happen.
There are usually some guys in the IRC channel who could assist you with it, as some debugging output might be helpful i think the best would be "live help".
check out #blackcoin via freenode IRC, webchat available via
http://webchat.freenode.net/?channels=%23blackcoin if you do not have an ORC client. Please be patient if you do not get an answer within minutes there.
So, you say not everyone with this wallet has this problem? OK, thanks for the hint - I'm not in a hurry, I will either wait for some more answers here or go to the link you provided, thanks again!
What are the specs of your machine?
I experienced those problems with both a Pentium D 3GHz and an Atom D330 1,6GHz system. Both were only running with 1 GB of ram, and both did not have this issue when fitted with 2GB of RAM, but in fairness I have switched a lot between Windows7 and Linux Distro's on those machines so I do not know if that extra GB fixed it.