GPC does NOT allow "uses" in the implementation section of a unit. That is, the following piece of code cannot compile. unit a; interface <something> implementation uses b; <something> begin end. In most (Borland-style) programs, moving "uses b" to the interface part (an obvious workaround; or *solution* if the current GPC behavior is a feature and not a bug) should not make a difference, but I imagine that there could be a few exceptions. The Turbo Pascal 7.0 manual says about this: "A uses clause in the implementation section allows you to further hide the inner details of a unit, because units used in the implementation section aren't visible to users of the unit. It also enables you to construct mutually dependent units." Jesper Lund