Comment 1 for bug 1249493

Implanted into a new layout, the part you posted loads without the error here. There might be something with the file, perhaps the encoding, but it's hard to tell from pasted text. Could you attach an archive of the whole layout?
$ tar -cvzf NextGen.tar.gz ~/.local/share/onboard/layouts/NextGen*

Also, check if that is the file that is actually loaded. The path can be found in Onboard's debug output. Look for the "Loading keyboard layout from" line.
$ onboard -ddebug

A missing librsvg2-common would cause a different error, a little later when images are loaded. 0.99.1 will fix this.