Why do I get a "security policy error" when launching my iPhone OS app?

Question

I created an iPhone OS 2.2 app some time ago and recently installed the 3.1 SDK.

When I try to run my app on my (3.1) iPod Touch, the launch window says "Error from Debugger: Error launching remote program: security policy error."

Viewing the iPod Touch's Console (via the Console tab for my device in Xcode's Organizer) shows:

Wed Feb  3 23:29:17 unknown SpringBoard[24] <Warning>: Unable to launch com.blahblah.Blah_Blah because it has an invalid code signature, inadequate entitlements or its profile has not been explicitly trusted by the user.
Wed Feb  3 23:29:17 unknown com.apple.debugserver-43[789] <Error>: error: unable to launch the application with CFBundleIdentifier 'com.blahblah.Blah_Blah' sbs_error = 9

I already sifted through a bunch of code-signing issues just to get it to build and deploy, so I think this might be something else.

Answer 1

After trying the above solution of deleting expired certs, I was still encountering this issue. Turned out I needed to launch the application manually once and accept the prompt asking if I really wanted to launch that application signed by that profile with that dev account. After accepting that, Xcode was able to successfully launch it subsequent times.