Thank you for the pointer.
I both Googled and searched the Forum itself before posting. Perhaps my wording was off.
For other newbies coming to grips with CS4, here was what I did to export an avi. sequence as a TIFF sequence.
1. Update your Media Encoder.
2. Select your sequence in the timeline.
3. File > Export > Media
4. Select TIFF (and don’t forget to check the box which reads ‘Export as Sequence.’ This is where I went wrong. Without the check off, the Encoder will just render one frame as a TIFF.)
Hope that helps for the Juniors out there.