By default, a service will run as the system account which will not have access to the network share. You should be able to change the service properties to run the service under a different account. (Log On tab on the properties page in the services MMC console.)

The other thing to look for is the drive letter trap. You as a logged in user can map remote shares to drive letters but the service won't know anything about it. Use UNC paths instead. e.g.

use \\server\sharename\path\to\file instead of x:\path\to\file

Try it and let me know if it works!

inman