Maintenance Plan For SQL Server 2005 64-bit Doesn't Work!

Hi all,
We have a SQL Server 2005 64-bit, and recently I upgrade from build 3042 to 3054 and I try to do a maintenance plan for transaction logs(TL) backup, including cleanup for two days (have full backup every night).

Problem I have is that I want the TL files to dump in a different location(due to disk space), so I put in the UNC path in the "Create a backup file for every database - >Folder:\FileServerTLDBLogs"

NB: if using the local drives, it work

Check List
Security:
- The account that I used to create the plan is an sa account
- The location that I dump the TL files, I have full access to the folder

SQL Statement:
exec xp_cmdshell 'dir FileServerTLDBLogs' (it list all files)

Is this a bug for 64-bit? because I can do this on SQL Server 2005 32-bit and it's work perfectly