well...is the one you're using the same one from bwchart.com site? it looks like it.
i think that replay viewer hasn't been updated in YEARS. in fact idk why it's version 1. whatever because they honestly never finished it. there are a lot of actions that are not titled properly, things like undefined or unknown it says. or maybe ?? or Ax or C-8 or weird short coded stuff like that maybe... at any rate i think your current problem might be the same as what i had but i figured out the solution to it.
your replay browser doesn't work very good. i think whatever folder it's searching needs to not have too many replays. i don't know what the limit is but if it steps into a folder with too many replays, it won't be able to browse them. so basically to us that program you will need to split up your replays into some kind of archived folders i think...25-50 replays per folder maybe. like i said idk what the limit is. but that's the problem i had which sounds like it's the same as yours if your replay browser isn't working. so try that, if it doesn't work, i guess you're sunk. try the new one from bwchart.com or w3chart.com whatever that site is but i think you got it already, pretty sure you do.
it's possible that latest patches of war3 have made this very old replay viewer completely unusable but i think the problem is just too many replays in a folder for the program, but yes the program was very underdeveloped, although it says it's version 1.01 or something like that i think the real version number should be somewhere around 0.3
