Have you tried importing the DMXs themselves instead of the QC?

Somebody else had a very similar issue:
https://psteamcommunity.yuanyoumao.com/groups/BlenderSourceTools/discussions/1/1741100099549325267/?tscn=1542222034

Why don't you just import the smd files one by one.

Is the scene you are importing into completely empty? For troubleshooting, I recommend you start a new instance of Blender, delete everything and try to import again. If that doesn't work, maybe the problem is in the SMD/QC files themselves. You can try to import the .smd files one by one to see which is the faulty one. Maybe even send us the contents of the QC.

I think the problem is Blender doesn't understand the file path you have provided. I recommend you simply download Crowbar to compile the model- it has an array of other useful features too.

https://pastebin.com/ktGhnK44
Here it is, sorry for the delay.
You can replace "SMDFOLDERPATH" with the path to the folder containing all .smd files and "MDLFOLDER" with the name of the folder inside the root/models folder where the compiled model files will go, you can name it "wow_props" for example.

As for the materials, you can use VTFEdit or VMTEditor to batch convert all the textures into the proper format and make the necessary .vmt files.

I actually had to deal with the same issue a while ago. I ended up writing an extremely simple Powershell script that took all exported SMD files in a folder and made a QC file for each one, complete with the required idle sequence, a collision model and so on. It allowed me to compile about 200 models automatically. I can't think of what horrible things an actual programmer will say when he sees my poor code, but I can send it to you if you want. It got the job done.

You can rebake one of the textures to the UV map the other one uses, so in the end both will use a single UV channel.

As far as I know none of the model formats Source uses at all support multiple UV channels, so I'm afraid there's no proper way around this.

I'm not sure I understand what you mean by ".agr".

Where did you get these QCs from? Did you decompile them? Did you edit them before you imported them?

Hello, sorry for the late reply- not sure what could be causing the error but- does this happen when you try to import the individual SMD files?