When you saved the profile sketch (.sldlfp file), had you clicked on the sketch in the tree to highlight it prior to saving? If not, then when you try to use the sketch nothing will happen. That's a common mistake. If that's it, open the .sldlfp file, click on the sketch in the tree, then Save, close the file, then try to use it in a Part again.
If that's not it, do you have the correct number of sub-folders in the folder you're pointing to at Tools > Options > System Options > File Locations > Weldment Profiles? So that when you try to use the Structural Shape function you go to the Feature Manager, select from each level, and finally select the specific profile that you want to use from the drop-down.
Please let me know if this works.
Your reply was very helpful. It gave me a clue as to what was going on. But to make it work, I had to delete the Default SolidWorks Weldment Profiles Location from the list of File Locations for Weldment Profiles in the System Options. Apparently you can have only one Weldment Profile location, unless there is some setting I have to set to allow both to exist.
I copied the file structure from the Default Weldment Profiles Location to make sure they matched.
Conrad - searching for other info I ran across your post. I just wanted to let you know that, yes, you can have more than one profile library. We do. It's possible this may be a limitation with the student edition.