Gnumeric File Reference "unknown workbook" Error
If you have file references in Gnumeric (you refer to different workbooks using a reference like:
... the references will not resolve unless the other workbooks are opened *in the same gnumeric instance*. This means, for example, that if you open Nautilus, select all the workbooks, and open them in Gnumeric, that your references will not work. Instead, they will all be quoted; that is, they will look like this:
Don't be alarmed -- your sheets have not been changed. Trying to manually remove the "'" will just throw up an error about a referral to an "unknown workbook."
The issue is that, as I said up top, all the sheets must be opened in the same instance of Gnumeric. It's not obvious in any way that open windows of Gnumeric may not be the same "instance" so this can be confusing. The solution is to open one of the documents, or a "new" Gnumeric instance, and then open the linked documents from within a single application instance.
I never used linked sheets in Excel, so I'm not sure if this is typical spreadsheet behavior or not. I'm frankly surprised that the sheets need to be open to be viewed... I think Gnumeric should be able to open linked sheets as long as the paths are right, but that's just me... anyway, HTH, HS (happy spreadsheeting)!