The feature of importing iPhoto Album needs the co-work of the iPhoto and iCollage. The loading error is related to some setting change of iPhoto. You can restore the default settings of iPhoto for a solution.
There is an alternative solution for loading more photos at a time: copy the photos to a new folder (Desktop is OK), select the Others Tab next to iPhoto and iSight in the iCollage application, drag the folder with all photos to the second blank space under Others. You can load all photos and start to work.
The problem is caused by the file security mechanism on Mac. If you have more than one account on Mac, the templates can't be shared among different login accounts.Could you please have a try of reinstalling the software and under current user's login account?
And please make sure it has been installed to Mac OS's "Applications" folder, need to drag the icon of the software to that folder to finish installation &launch it there. Also you'd better repair disc permission by Mac Disc Utility tool.