It is possible that sections of the update did not complete properly and must finish installing before the EPC will open. Please attempt to restart the update to ensure that all sections of the update are finished installing. You can restart the update by either:
Re-inserting DVD1 into your DVD drive.
Locate the Computer (or My Computer) icon and double-click it.
Locate the appropriate DVD, right-click and choose Open.
Locate Setup.exe and double-click it.
If the error 500 persists, please contact support.