Win7 doesn't handle PCMCIA on older hardware well.
You might try this:
1. On the first reboot, boot from the DVD instead of the HD.
2. Select the Windows installation you just created, then select repair.
3. After scanning and finding no issues, you will see an option for advanced repair options.
4. Open a command prompt.
5. Rename c:\windows\system32\drivers\pcmcia.sys to pcmcia.wah
6. Reboot the system; if that was in fact your problem, install should now proceed.
There is a way to get the PCMCIA slots working after the fact, if the above actually works.