Fatal error: Cannot declare class Error

Hi everyone! I have osTicket version 1.7 i guess and after a migration i have an error:

"Fatal error: Cannot declare class Error, because the name is already in use in /home/xxx/public_html/soporte/include/class.error.php on line 43"

Anyone can help me?

1.7 has not been supported for many years.

My guess is that the new system you migrated to is using a version of PHP that is too new for your ancient version of osTicket.