We have an AE project that contains Photoshop elements that opens up on every computer fine except one. For some reason on this computer one of the layer's anchor point changes upon opening, thus moving it out of position. When it is saved on this computer and moved back onto another one, the layer is back in the right place.
Are you using the exact same version of AE and Photoshop on every system? There have been various issues with PSD files in CS3, some of which were only fixed by the 8.0.1 and 8.0.2 updates, respectively. Also, if you have different versions of different Adobe products on each system, some shared libraries for PSD handling might be of a different version and thus trigger odd behaviors.