Hello when i try to open a dwg file i get the error demonstrated in the screenshot. Could you please help me with that?

Basically the problem has nothing to do with CadLib. What the dialog tells: The offending DXF/DWG refers to an SHX file which is not available for the target application. SHX files are shape files, which usually (but not always) contain fonts similar to TTF. Which SHX file is missing will probably be told in the next dialog when you choose the "Specify a replacement" option. For legal reasons CadLib does not come with any SHX files, but is able to load them and display texts using them correctly. If no matching SHX is found CadLib is using a substitute font (see my answer here for more info about font loading and substituting). References to SHX files are usually found in DxfTextStyle objects, so you should check them first. But SHX fonts can also be directly referenced from DxfMText texts via escape sequences, so locating all references to a given SHX might become complicated. Basically you can either provide the missing SHX (but be sure its license allows you to distribute it), define a replacement or ignore the problem. In the two latter cases your file is probably displayed differently in places where shapes from the given SHX file are used, which is usually in text entities. - Rammi