You can manually zip the save in question, along with any CrashDump files in the '..\SteamApps\common\Divinity - Original Sin\Shipping' folder, to email to supportdos@larian.com. Perhaps also include your dxdiag report (click Start or WinKey-R, type in dxdiag and hit Enter, then in the window that opens, wait for it to finish and then click the Save All Information button).
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin\PlayerProfiles\<ProfileName>\Savegames' folder. In Windows Explorer, right click on the save folder and select 'Send To | Compressed Folder' to zip it.
