camel-karaf-commands depends on a version of the OSGI framework not packaged with Servicemix 4.5.1 . You can attempt to install the required package from an org.osgi.core JAR but your mileage may vary.
Karaf 2.3 and 3.0 comes with the required package, but Servicemix 4.5 still uses Karaf 2.2