Hmm have you got the new version inception_0.1.1_armel.deb? You'll need that version instead of 0.1 if your phones fully updated on PR1.2, though if you have the latest version, and judging by the error message you probably do, using the wrong filename is the problem.
You need to type "dpkg -i inception_0.1.1_armel.deb" instead of "dpkg -i inception_0.1_armel.deb", the version changed since those posts.
Also I recommend once you've typed "dpkg -i in", hit the tab key and it'll auto complete the file name.