Actually you can fix this without RT7Lite, just mod your XML file (i use WSIM from WAIK) or edit it manually (fyi the sample only creates two partitions, but you'll get the idea, my guess you want to create 3 primary partitions)
If that don't help, then we'll need to look into which settings pass they are being run from, attach your XML so we can determine real cause of issue.
<!-- Create primary partition, 20 GB -->
<!-- Create extended partition and fill the rest of the hard disk -->
<!-- Create logical partition within the extended partition, 6 GB -->
Edited by MrJinje, 10 September 2013 - 07:18 AM.