How can I deploy an iPhone application from Xcode to real iPhone device without having a US$99 Apple certificate?
It sounds like the application isn't signed. Download ldid from Cydia and then use it like so:
ldid -S /Applications/AccelerometerGraph.app/AccelerometerGraph
Also be sure that the binary is marked as executable:
chmod +x /Applications/AccelerometerGraph.app/AccelerometerGraph