Here is a simple test user command defined with a template of folder/K
DOpus.output "folder: " & data.func.args.folder
When executed as follows, the debug output is shown
Test folder="c:\program files"
Test folder=c:\program files
Since the supplied string c:\program files contains a space it needs to be quoted in order to be treated as a single entity. When executed without the quotes I expected the argument for folder to resolve to c:\program and the balance of the supplied (unquoted) string to be orphaned since the template only defines one argument. The resulting error is something of a surprise