that is because the error says "two strings, a pattern and a replacement" but should say "two strings AND ONLY TWO STRINGS, a pattern and a replacement "
you only get one shot at it, as you have discovered.
if your filesystems are not similar --on our primary we have 7 logical file systems and the standby has 2 logical filesystems [*note: not by *my* design ]-- you have to rename the files in the controlfile (normal methodolgy except this is done after ALTER DATABASE MOUNT STANDBY DATABASE ) or as they are added
ALTER DATABASE CREATE DATAFILE 'primaryname' AS 'standbyname';
check out the the oracle white paper on standbys or oracle docs on standby. it alludes to this, but does not actually *tell* you how to do it.