when trying to record a payment in AR-C, a message pops up: "A record was not found in FILELOC for file ISGLDATE.BGP -4" and after that "An error message was not found in ERRMSG.B file . 405
 
I run the update again and forced file ISGLDATE, but get at the end of the update a  
FATAL ERROR
File EvoERPupd.scr line731
you have tried to access a file tha has not been previously opened, or the file number value FNUM passe was 0
 
Any ideas  

Read the Troubleshooting section of the installation instructions.  "A record was not found in FILELOC for {filename}" means that the update process did not run properly.