The first thing is to check and see what the RSS feed displays. Place it into a feed reader and see how many episodes show. Just because the podcast has that many, they don't necessarily put links for all the episodes in the RSS feed and PodTrapper can't pick them up. If that checks out alright, confirm that in the Storage Settings under "Max episodes to read from feed" has the right amount, so in this case if they have 280 you can set it to read 400 episodes.
Hope it works out, I've done the manual way a couple times and it sucks.
