This error seems to happen randomly and especially when trying to send e-mails. Apparently it's a long-standing GNome bug but is also partially the default of Thunderbird depending on who you ask. There is no known fix that I'm aware of except to upgrade gnome and the gvfs package but this is not an option for older versions/distributions.
An error occurred while loading or saving configuration information for thunderbird. Some of your configuration settings may not work properly.
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
Bad key or directory name: "/desktop/gnome/url-handlers/GMT+02/command": `+' is an invalid character in key/directory names
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