Is there an upper limit to the number of data links in a dwg?

[jeff_rivers]

I have a pretty complex drawing with about sixteen data links to four different spreadsheets. This morning I created two new data links, and something odd happened.  When I attempted to add the tables to the drawing, everything went well until time to place the table, and the command just exited.  The phantom table didn't show up at the crosshairs, the command line cleared, and no table was created. 

Was that just a fluke, or do data links get flaky if a drawing exceeds a certain number of links? 

[jeff_rivers]

Replying to add more information, for future seekers.  

Previously, I've data linked to Excel spreadsheets, and the regions linked to contained some merged cells.  

Today, Civil 3D decided it was Not Happy About Linked Cells, and that was the issue.  I tried creating new spreadsheets, restarted, rebooted, and it wouldn't create a data link at all if the region I was linking to contained any merged cells.  

Via trial-and-error I discovered that as long as the region I was linking to didn't contain any merged cells, the data link worked fine.