I'm running Gnome 2.10 and Openoffice 1.9. The new version of OpenOffice uses .odt as an extension, which Gnome thinks is an archive file. This makes some sense as it is a zipped file but it really should belong to OpenOffice. I found a fix on the freedesktop.org bugzilla. Here's the link: https://bugs.freedesktop.org/show_bug.cgi?id=2265 I edited my /usr/share/mime/packages/freedesktop.org.xml file and this seems to fix the problem.
Created attachment 59156 [details, diff] Patch to add OpenOffice mimetypes for .odt and related opendocument formats. Here's the diff file from my system.
this is in shared-mime-info-0.16