@Shun - are you using our latest 3.2.26 update? This looks like an issue brought out by that - we changed the way a couple of formatting tags work in that update and it seems like this database was using those tags in a nonstandard way. (main tags affected were the 'block' tag U+EAC3, which as far as I know we've never documented anywhere, and the 'color' tag U+EAC1, which I'm not aware of any widely-circulated user dictionaries employing) We never embed those tags directly in any of our dictionary databases (they're all generated by another, completely undocumented part of our database system) so we thought it would be a totally invisible change but it seems like there may have been a few user dictionaries using those tags after all.
Anyway, fixing it should just be a matter of replacing every string of two @@s with a string of four @@@@s - do a find-and-replace on the .txt file to make that change, then import it and it should work fine.
(re that color tag, if anybody does want to use that, now, instead of putting the color in the lower 15 bits of two characters, you put it in the lower 8 bits of 4 characters, with EC00 as the top 8 bits; we made a terrible decision years ago in allowing our numeric format tags to potentially overlap with valid characters and now we've finally fixed that by confining them all to the PUA)