Hi,
Does your track show up at all in the list of tracks in your new 998? It may be that the track is not getting imported - test this by putting your card with the track into your unit, and see how many tracks the unit reports as loading (assuming the track is not already in the unit memory). If the track doesn't show at all, then I suspect it is because the newer version HB software is more careful about importing incorrectly formatted data. This is conjecture to some extent on my part, but I did notice a change with the import behaviour of tracks when updating one of my units to v6 software. You could try loading your old track into HBPC and re-exporting and see if this fixes the problem.
If it is of any help - ReefMaster makes tracing or drawing of tracks for display on a HB unit extremely easy. You can draw a freehand track (in a UserMap) or enter explicit lat/lon points to create a path, which can then be exported to a Humminbird track. This is designed precisely for the kind of task you have - state borders, marine park zones etc. You could accomplish what you need very quickly, and if you did so within the 14 day trial period you wouldn't even have to buy the software
Alternatively, send me your existing track - matt(at)reefmaster.com.au - and I will be happy to assist.
cheers,
Matt