$scriptdir (available only from within a script file and not from the command line) is the path to where your script is saved. It's an internal mIRC identifier and shouldn't ever give errors. $scriptdir\TopScores.hsh just says to go to the script's location and find/save the hash table there. The $qt part puts quotes around it so you don't have issues with spaces in the path. So there is no reason that I can see for why it won't work.
It's fine to remove that and just save it in mIRC's main folder. Just remember to change ALL $scriptdir parts dealing with that filename (including the /hsave and /hload commands) or you'll have problems later on.
