IIS Synchronizing Data Error

hi..need help here,
I sometime get error when syncronizing data at New Subscription Wizard, and sometime I dont.but right now i cant sync, this is me error messages :
"Synchronizing Data (Error)
Messages
A request to send data to the computer running IIS has failed. For more information, see HRESULT.
HRESULT 0x80070002 (28037)
The operation could not be completed."

I've turn off the firewall, turn off the antivirus, plug the LAN cable but still error (Maybe it has to do with it).A long time a go I've had this error, and then I decided to reinstall SQL Server and try it again and it work, now it back to me again, do I have to reinstalled it again(hopefully it solved my problem)?or any otherway?

And want to ask about SQL Mobile, When I choose the Merge, the uniqueidentifier will be add at my table right?what should I do at inserting query process, I cant just insert it with NULL value right?
After my subscription doing input data, is it my publications will be automatic updated?
I'm little lost here..need advise

Its a miracle.. "_" now I can sync it without any changes on my computer, I give one more shot try to sync after I write this thread and then it works!!

but still curious why sometime I can, sometime I cant?

and still know about uniqueidentifier, please..