Assuming you have copied the ROM and Google Apps onto your phone's SC card.....(you will need both, even though you aren't obliged to install the Google Apps).
Are you sure you wiped the phone memory, cache & dalvik cache through recovery? Hoping you also took a Nandroid backup.....
Once you have done all the wipes, try installing the ROM.zip again.
If this still doesn't work, try and get hold of an earlier version, as I have heard that some people had difficulty installing 5.3 on top of stock.....
If I managed to help you, don't forget to thank me