The error message below will be displayed (during slide creation) if one or more songs in the group has a # character on two consecutive lines.
For example:

Here is the error message:

Error message text:
"The specified parameter has an invalid value"
Slide creation will abruptly stop before the error message is displayed:

To resolve the problem (until it can be handled better by the program) open the song that failed to generate slides and remove one of the # characters from the song using the Song Editor. Only one # is needed to cause a slide break. If you want to include a blank slide in the song, then use the Blank button in the PowerWorship main window while editing the song group. A blank slide will be inserted with a black background.