Hack shield can be a very finicky thing.
The best option may be to full uninstall the game then reinstall it from scratch. Even that may not be a 100% guarrentee as when the Windows 8 preview came out, a friend of mine wanted me to play DFO(uses hack shield as well) and with the exception toe getting kicked from time to time for "speed hacking"(I guess win8 must have been a speed hack).
It worked fine for a while, then one day just started doing the same thing you mention. Long story short support wanted nothing to do with trouble shooting any thing on an OS that was "not supported yet"(it was less then a month before release at this point). All I wanted to know was the location of ALL game files(so i could make sure they ALL get removed) as clearly even after a full uninstall reinstall, the game still remember game settings and stuff. Either way, it was never solved.
Worst case, I would get a hold of the game maker(nexon?) if you have a supported OS I would hope they would be a little more helpful.