more on the railroading front:
Never PLAN to capture the party
-this almost always ends up as railroading as you make stronger and stronger attempts and dice fudges to make it happen so your plan will work
Never CAPTURE the party if you can avoid it
-Once you've captured the party, they will want to escape. This means you will have to prepare for it. You'll need to know how they are tied up (or not), where are they housed. The feeding schedule. The guard rotation. The rope quality, chain quality, lock quality will all need to be known. Plus, they'll want their gear back. The end result is, only capture the party as a last resort (most likely to save their lives as a DM). And then, if you don't have all of that documented out, pause the game and figure it out.
Never strip-search or violate the PCs after you capture them
-Some DMs and players might not mind it, but with a new group, you can't guarrantee they won't take offense. Some specific examples, female players may be VERY uncomfortable with having such liberties taken with their characters. 1/5 women in the real world are raped, and this is a sensitive subject to them (heck that stat is just the US alone). In addition, this just further weakens and humiliates the characters, giving them no chance of escaping (and thus ending the game). Consider the "capturing" that happens on TV shows like startrek or Stargate. Their guns get taken, they get tied up, and thrown in a cell or marched along to a destination. It's fine to pat them down and take anything obvious. But ultimately, you're foiling the rogue in the game by taking her hidden lockpicks in her hair, and that's just bad DMing.
And yes, I've played in a newbie DM's game where I had warned him to follow rule #1 before he wrote the adventure, and he promptly broke all three. And we had 2/4 players were women. That was the last game under that DM. He had designed his adventure on the premise that we WOULD be captured. This made that whole encounter un-fun (and I managed to be the only one not captured through lots of hard work and running away). He followed up by having his villain be "smart" and completely strip-search all the prisoners (further weakening their position and angering the female players). The result is, everyone pretty much decided that the campaign sucked and that was the last game. Even the DM knew it sucked, but failed to grasp why he had broken any "rules"
Janx