no child data folder of that name exists

I want to invoke an external operation in a xop from my function in a procedure. i get this error with every operation,which i want to invoke in this xop.

For example, if i want to invoke these operations( i know they dont mean nothing to you);
MES 40,0,1,0 or SPT 0,0 igor shows me the error.

What kind of error is "no child data folder of that name exists"? Why am i getting it?
The error "no child data folder of that name exists" is pretty self-explanitory. A child data folder, is another name for a sub-folder. For instance, if you place a new data folder within the root folder, root is the parent and your new folder is the child.

I'm not sure why you are getting this error, as I do not know your code, however it may be how you are searching for this child folder. For instance, if you have three folders within the root folder, they are each children of root. So long as your current data folder is root, you can find these children. However, if you set the current data folder to child1 and then search for child2, you will not find it as it is not a child of your current data folder.

Take a look through your code focusing on sections which set the current data folder.

When it comes down to it, the most likely causes for this error are as follows:
1. The folder does not exist
2. The folder has the wrong name
3. The folder is not a child of the current data folder