When Connecting Windows XP and older to a Windows Vista ro newer machine, you may run into issues. Go to the commanf prompt and execute a NET USE to map the network drive. If you get "System Error 58", try the following in windows registry.
Left Pane: Local Computer Policy \ Windows Settings \ Security Settings \ Local Policies \ Security Options
Right Pane: Network Security: LAN Mananger Authentication Level = NTLM (not v2)
This uses the old authentication rather than have windows try the type it detects. Finally, their is a registry setting that should be set on the server that changes the allocation of resources: