After updating to the latest 2.0.1 version of Titanium Studio, i got this error while trying to deploy my applications:

package org.appcelerator.titanium does not exist

import org.appcelerator.titanium.TiStylesheet;

Followed by a bunch of other errors related to missing Titanium libraries. And in the end, that’s just what it was. For some reason, Titanium Studio had set my SDK path to an invalid value. To fix this issue, go to Window -> Preferences -> Titanium and check that the Titanium SDK Home path is set to a correct value.