You have a corrupted record in one of the files used in the recalc - probably WOMAT or, if you use labor and routings, WOLABOR.  Since you have Evo, use the Evo version of Maintain database on those files and you should be able to find and fix or delete the corruption

Try going to the first and last record using each of the indexes.  Typically something corrupted is going to sort to one extreme or the other.  My experience indicates that it is typically the date fields that get hosed.  If you purchase direct for WO it could also be the OUTPROC file.
 
Unfortunately, reindexing probably won't fix it but you can try.  Make sure you back it up first.