I use Google Apps as do many of my clients and I can confirm this as an issue that affects both the paid and free versions of Gmail. The advanced attachment features, which use Flash, do not work with network attached file shares on Windows 7 and the newest version of Google Chrome (10.0.648.127). There is no visible error message, as far as I have encountered, but the file is not attached. I still have to submit tickets to Chrome and Google Apps but as a work around you can enable the basic attachement features under “Settings” (it’s at the bottom of the that page). It always tough to go backwards from an interface standpoint. Hopefully this will be short lived.