The thing is that I need to load an entire assembly and part of its comonents must be defined as a fixture from CAD to be read as a fixture using a CAM software (EDGE CAM)
You have not uploaded the IPT's with your IAM....
This is an easy one -
Create a new IPT..... Then just click on Derive open your IAM and simple just save it as an IPT.
Here is a tutorial I done for someone else and another question but it is just the same steps only you do not want to scale it just save it as IPT.
Opss sorry I forgot to add like to the tut...