SO Invoice Data entry

SOLVED

Hi guys,

I'm trying to clean up our inventory a bit, but I'm having trouble with the Delete and Change Items task. 

What is basically happening is every time I try to enter the task, an error message pops up saying "You cannot proceed with unposted data in SO Invoice Data entry."  

So far I've read that the best thing to do at this point is to reinitialize the data files for Sale Orders invoice, but I would like to get some other input, and ideas on the best way to proceed from here. 

Thank you!