This has worked on the machine previously. here is some of the info you requested:
Premiere Version: 4.0.0 English, i'm installing 4.0.1 now to see if it helps
OS: Windows Vista business 32 bit up to date.
CPU: intel core 2 t7400 2.2ghz
VIdeo Card: Nvidia GeForce Go 7950 GTX driver version 184.108.40.20609
Audio Card: Sigmatel High Definition Audio CODEC version 220.127.116.1143
Just guessing here, since most required info is still missing, but it looks like something in your timeline or lacking disks. You are using a single hard disk? BAD! Use at least three separate 7200 RPM physical disks with eSATA connections.
It seems to be working after installing the 4.0.1 patch.