Failed to install *.apk on device '*': Local path doesn't exist

I'm recieving the following error when trying to run my app on my phone. It used to work, but it has now decided to always give me this error and I can't figure out how to get it working again.

Failed to install *.apk on device '*': Local path doesn't exist. 
com.android.ddmlib.SyncException: Local path doesn't exist. 

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I've tried restarting the computer, the phone, and the debug mode, none of which have worked.

Edit: I get this error both on my phone and on the emulator!

Ok I figured it out. I had moved the apk file to a different directory (trying to fix a different problem) and eclipse was too stupid to figure it out. As said in the comment below- fix the problem with Project->Clean...