I've never had great luck with PowerPrompts/IWR. This explanation comes directly from Cognos:
Description:
Is it possible to publish several PowerPrompts application into the same report set in IWR?
Solution:
Yes, but you can not put them all in the same folder if they have HTML pages with the same name.
The most typical page with the same name is the "EntryPage". However some users get around this by renaming "EntryPage" to another name which is unique to each application,but the best way is to put each PowerPromtps application into a separate folder. Then put the application folders in the same folder as the reports and catalog to publish.
In order to let PowerPrompts application know where to find the report to run, Relative addressing must be used in each PowerPrompts application when specifying the report to run in the application properties in Developer Studio.
For example, "D:\Program Files\Cognos\cer1\samples\Impromptu\Reports\PowerPrompts 1.imr" under "Report to run" must be changed to "..\PowerPrompts 1.imr" assuming that "PowerPrompts1.imr" resides on the folder right below the PowerPrompts application.
This way no matter where the PowerPrompts applications and their associated reports get published, PowerPromtps always looks for the report in one folder below the current directory.
For example the directory structure for 3 PowerPrompts application each running a separate report looks like this:
D:\Program Files\Cognos\cer1\samples\PowerPrompts>dir
Volume in drive D is Free
Volume Serial Number is B8EB-4BC0
Directory of D:\Program Files\Cognos\cer1\samples\PowerPrompts
02/19/2002 08:35p <DIR> PowerPrompts1
02/19/2002 06:45p <DIR> PowerPrompts2
02/19/2002 06:45p <DIR> PowerPrompts3
06/16/1999 11:37a 352 PowerPrompts1.imr
06/04/1999 04:00p 140 PowerPrompts1.imr
06/16/1999 11:37a 252 PowerPrompts1.imr
06/10/1999 02:06p 400 PowerPromptsCat.cat