Error -50 when copying folders to NTFS SMB share

Hi AFP548, I have about 60 Mac clients tied into a Windows AD environment that uses an EMC NAS system for its network storage. Unfortunately no one running Snow Leopard can copy a folder to any of the share points, regardless of permissions - it gives a "Error code -50. Operation could not be completed because an error occurred". However, a terminal input of cp -R folder /Volumes/theserver/Destination completes successfully. This happens regardless of if the share is mounted using cifs:// or smb://, and does not occur if SMB sharing between Macs, only to the NAS. Spoke to Apple enterprise support and they can't troubleshoot unless I pay 675$ for "Windows Integration Troubleshooting", so I'm kind of stuck here. Has anyone else seen this? Chris