Network Location appear The local device name is already in use..

I have Windows Server 2003 Domain Controller and have move the fileshare files to a new Windows Server 2008 R2
The network has both Windows XP and Windows 7 clients. It's only Windows 7 they losing the contact, in network location in the clients

The net disk appear a red cross and error message is ... The local device name is already in use..This Connection has not been...

I have also test a new re-installed a test PC with Windows 7 .. same there...

So we can exclude the fault on The user Profile and folder directions..

The logon script look like that

***********************************************************

net use /d * /y 

net use h: \\iw-srv-file\home$\%username% /persistent:yes

rem NetDiskar

net use i: \\iw-srv-file\DSIK1
net use j: \\iw-srv-file\DISK2
net use t: \\iw-srv-file\DISK3
***********************************************************

I have also add on the Windows 7 Clients - "Network security: LAN manager authentication level" to "Send LM & NTLM responses".

Any ideas ?