We have had a lot of XL spreadsheets deleted today after AVast reported the “MX97:CVE-2009-3127 [Expl]” . We have checked the particular files on virustotal.com and only Avast and gdata report them as having a virus. We suspect that the offending files have a pivot table in them.
Did you send these files to virus@avast.com? See support page http://www.avast.cz/eng/technical_support.html