Length limit for project

I am just learing to use DVDSP4 so this is probably a real simple question. I have burned a couple of DVD's under 60 minutes with no problems. Now I have a program that is 90+ minutes and comes up as 5.9 gigs on the guage at the top of DVDSP4.
Is 60 minutes the most that can be burned?
Are there settings to change? I can't find them.
Should I compress it using Compressor? I see that it has a 90 min & 120 min setting.

Thanx Barry

G4 dual 1gig Quicksilver, Tiger

The encoded MPEG file size is the result of the bitrate used to do the encode. You can't use a bitrate of 6.5 Mbps and get 2 hours onto a DVD-5. Slow dow the bitrate during the encode session and the resultant file sizes will also be smaller.