Linking the Project Milestone table with A/R Invoice

I want to put the milestone description on the A/R invoice. The ProjectMilestone table comes down into Crystal just fine, I update the dataset then go to Links. I am trying to link the Milestone table to the INVCDTL table by company, invoice number and invoice line. I make the links and then Crystal crashes and ends abnormally. I am just wondering if this is normal behavior if the links are wrong or if this is a Crystal issue.