Report wizard

Hello,

I had created a custom module using the module loader called Platform and have created a relationship between Account and Platform (one to many). Everything was fine. Now I was trying to create a report using the Module Platform but I wanted field from the related module section on the left (Assigned to) from another module. 

So it pulls it like this

Platform > Distributor > Assigned to > User name 

but the minute i add that field as a column in Choose Display Summaries, all the data disappears? 

Any help would be appreciated