Try building a list/report style layout that references the portal records directly instead of using the portal. Printing from layout with a portal often encounters limitations that are best solved in this manner.
Describe the purpose and structure of your two tables as well as your report and then I may be able to repeat the above suggestion with more detail to give you an idea in how to go about this.
Phil, Thanks for the help, I need information in the header and a Sub-Summary parts, which is why I print the report the way I do.
Not sure this would work in the LIST Layout.
If you are using header and sub-summary parts, then you are working with a List layout and the method of which I've given you just the barest outline, will work.
Let's call your two tables "Parent" and "Child". You are currently trying to print from a layout that uses Parent as its reference table and Child records are displayed in a portal that you have placed on this layout.
Instead, Create a layout that refers to the Child table
Place the Child fields that you were trying to print from your portal into the Body.
Place any related fields from Parent in header, sub-summary, and other such parts as you need.
Sort your records to meet the required sort order of your sub-summary parts and you should get the report you want.
Try this and see if it works for you. If you have problems, describe your tables in more detail and I or another forum participant will help you out.