Melanie - this seems like a separate issue than this bug report, which was caused by gnumeric and which is fixed in Ubuntu for quite some time. I believe filezilla has incorrectly modified your mailcap file and that is what is causing this, subsequently a bug report should be filed about filezilla. You can easily do this using the command 'ubuntu-bug filezilla' on your Ubuntu system. Please also add your mailcap file to the new bug report. Thanks in advance.
Melanie - this seems like a separate issue than this bug report, which was caused by gnumeric and which is fixed in Ubuntu for quite some time. I believe filezilla has incorrectly modified your mailcap file and that is what is causing this, subsequently a bug report should be filed about filezilla. You can easily do this using the command 'ubuntu-bug filezilla' on your Ubuntu system. Please also add your mailcap file to the new bug report. Thanks in advance.