pivot table error but still updates

I have a workbook with 6 worksheets. One is the source file for my pivot tables, three of them are data source files for my pivot table source file and one is a smaller pivot table on it's own sheet . Everything has been working fine and suddenly i get this message when I refresh my pivot table data: Cannot open PivotTable source file 'C:\my name on HD\folder name on HD\[name of workbook]name of worksheet'.

I have removed all protection to see if that is why it's not working. My summary worksheet, the one with the pivot tables on it, still updates from the source even though it says it can't open it. Does this have anything to do with the fact that it's looking for the source file on 'C' drive? If so how can I change it so it looks for the data in the workbook?

If you'll upload a sample file I'd be happy to take a look.