Sporadically, one of our computers will no longer load EVO or DBA.  Usually this is associated with a Btrieve error.  Today, we have two computers unable to sign on to either DBA or EVO.  On one computer the error is Btrieve 3106 on both EVO and DBA plus on EVO it returns the message that it cannot locate FILELOC.DBF in either the DBAMFG folder OR the ISTS folder.  Suggestions on correcting this problem?