What does "Tie-in dvds" mean?

This sounds like non-fiction.
A DVD (that you have produced) which relates to your subject.
For example for education we will get a text on teaching techniques and an accompanying DVD that can be played which shows teachers using the particular curriculum or testimonials from students.
A tie-in means something related to your subject.
The questionnaire from my publisher (although I write fiction) asked similar questions of me i.e.
Do you have any other ideas or thoughts about how your book might be sold or promoted? Any organizations that should be notified (give names and addresses). etc.
BUT
You need to ask your agent you need to ask your agent you need to ask your agent.
If asking a question puts you in peril then you do not have an agent who will be useful to you.
A short email stating: "I am unclear about this question." should not be a problem with a reputable agent.
Fifty emails from you asking one question at a time over the span of five days would definitely lead to "ichy chemistry"

JMHO

Is this question coming from the agent or from a publisher?

I have to say that this sounds like an odd request to me, even if your book is nonfiction. Why DVDs specifically?

Feeling you can't go to your agent with such questions is not a good thing. You need to be able to turn to your agent for advice; it's an essential part of the business relationship. If your chemistry is so poor that you're nervous about asking something at this stage, what's going to happen when you're at contract negotiation stage? Subsidiary rights sales stage?

- Victoria

I totally agree with Orion and Victoria. Having an "itchy" relationship with your agent is not a good thing. The more important question right now may be why you feel uncomfortable asking your agent business-related questions. If it's something YOU did, knock it off. If it's something your AGENT did, address it NOW -- before your relationship gets even more tenuous. He or she won't be able to help you if you don't feel like you have a trusting and straightforward relationship.

Kristen

A tie-in is anything that is marketed on the coattails of something else. It piggybacks on the popularity or success of another product, e.g. Star Wars, Narnia, Spongebob. So you get tie-in action figures and pjs and lunch boxes etc. Conversely, the tie-in can be a heavily discounted premium that's packaged with another product as enticement to purchase, such as a Christmas CD of country songs for $1.99 with purchase of 10 gallons of gas. Or, as Orion said, something that comes packaged with the book to add value.

Basically, you're being asked to think about licensing rights--ways to extend your idea into different media and markets. It may be that the tie-in DVD question is just part of a form questionnaire and it may not apply to your book. But don't dismiss the idea too quickly til you think it out. There are a lot of creative ways to tie-in. For instance, big corporations will often buy huge numbers of products and slap their name on it and give it away as a premium, or bundle it with one of their products. I recall Compaq doing some such promotional thing with a Sting CD at one time.

But, as everyone else has said: ASK YOUR AGENT