Hi andre104,
If Borland is selling Tasm then it's safe to tell that the product is commercial. Tasm is an outdated assembler and it does not support the MS COFF object file format which is used by Pelles development tools. I would suggest you to have a look at Poasm, Pelles Macro Assembler supplied with Pelles C. It's a very poweful tool and it's maintained regulary by Pelle.