@User: If magic does not show any errors, then there are probably not any errors; you might want to set "drc style drc(full)" to get a full check (should not slow things down much unless the layout is very large); The default style "drc(fast)" is good for standard cell layout but assumes that you are abutting cells normally. Note that in this case "abutting" means that the inner bounding box edges are aligned. There are two bounding boxes---the abutment box (inside) and the extent of all drawn geometry (outside). The inside box is the one you care about when aligning standard cells.