RMAN-03009: failure of backup command on ORA_DISK_1 channel

I encountered this error while using RMAN CONVERT DATABASE COMMAND. The exact error was as follows:
RMAN-00571: ===========================================================RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============RMAN-00571: ===========================================================RMAN-03009: failure of backup command on ORA_DISK_1 channel at 07/27/2008 12:23:09ORA-09210: sftopn: error opening fileOSD-04002: unable to open fileO/S-Error: (OS 3) The system cannot find the path specified.

I was trying to put the converted files on z:\ which was a mapped drive. After opening an SR I came to know that I was to use UNC naming i.e. I had to use \\servername\sharename in the place of z:\.