I've had the same problem.  Just got a brand new loaded XPS Gen4, with a NEC ND-3450A  DVD burner.   During the install, it asks for the second disk.  I put it in, and then after I click OK, the install program just stops responding. 

How many copies of Myst IV has Dell given away that can't be installed, I wonder?  A lot I'm sure.  I'm surprised that there aren't a lot more postings about this yet here.  The Ubi site and other sites are flooded with postings on Myst installation issues on a variety of systems.  (understand that it isn't a DELL issue, it's a Ubi issue concerning the copy protection they chose to implement)

There are a variety of causes, but after a few hours of reading through other message boards it appears that most likely it is the DVD RW drive installed on my system  (An NEC ND-3450a).

I went to the NEC site to see if I could get a firmware upgrade for the 3450a, and it's not even listed as a model.

If anyone has been able to get Myst IV installed using a NEC 3450a, or if DELL has identified a fix, I'd love to learn how.

Thanks in advance for any info anyone can provide.  It was a nice bonus to get Myst with the purchase of my new system, and I'd love to be able to get it installed.

Scholl