Mapping Drives

I have having an issue mapping a drive to a Windows XP PC (home edition) which runs our security cameras.
I know I have done this in the past by creating an administrative account on the XP machine (Home) and using that user name and password to map the drive.
From a windows machine I map the drive

using XPHomePCname\administrator and then the password

I keep getting the message

the specified network password is not correct.

I have reset the password a number of times and I cannot be entering the password incorrectly

??????

Try specifying the computer name of the file host machine by putting this in the username box

Machinename\username