I never had this problem that others reported about not reconnecting after hibernating (sleep) a Win7Pro64 system ... UNTIL ...
now. Which is after I upgraded to SP1 a couple days ago. This is super crazy ! And I am unable to re-connect without rebooting the entire Win7 system. Log-out user and re-login does not help.
Interestingly ... although it is still primarily a Win7 problem ... I have **NO** problem with two other servers that have each one shared drived exported. Win7 connects (and always has) to them just fine. Before or after sleep mode. In other words ... there's a fix REQUIRED in NASLITE !
If I use Windows Explorer to "disconnect" and then re-connect the Z: drive I get the following error pop-up window:
"
The mapped network drive could not be created because the following error has occured:
The specified server cannot perform the requested operation."

Edit: additional info: If I use the command "net use z: \\<ip>\Shares" in a "DOS" session, I get the same message, except that the first line says: "System error 58 has occurred."
Of course, googling for this error ... is not all that helpful. Again ... my two other servers (ClearOS) are behaving just fine !
I don't want to reboot my Win7 machine multiple times a day ! 
Edit2: More info. I disconnected Z:, rebooted Win7. I connected Z:, it connected fine. (As a reminder): An old known issue: the Z: drive shows as "4.56 MB free of 15.4 MB", whereas my ClearOS drives drive show the proper free space (in the GB range). I have no more time right now to investigate this, but will update if I find something new. In the meantime, I think it's time Ralph and Tony get involved a little.