ISE Project Navigator has the ability to launch iMPACT in batch mode in order to generate PROM files. The intent is for iMPACT to automatically create the PROM from the .cdf in batch mode, then give control back to ISE.
However, my .cdf loads with several warnings, and the process then fails with the following error:
"ERROR:iMPACT:909 - setSubMode is required before this operation."
This problem is fixed in the latest 5.1i Service Pack, available at:
The first service pack containing the fix is 5.1i Service Pack 1.