Sync offline changes with online sheet

First of all, great suite of apps. I'm sold and am looking forward to expanding my usage.

I have had an issue trying to sync offline change with the online spreadsheet, though. I make a change to an offline version of the workbook (a copy exported from the online version and has the same name as the online version), connect to the Net, login to Zoho, and try to save using the Zoho plugin save feature, I then receive the message that they sheet does not exist online and it asks whether I'd like to save it online. If I say yes, a new copy is created in my account.

Any suggestions? Thank you!