Dataports, like the other objects in C/SIDE, must be compiled before they can be run. You can compile a dataport when you save it, or you can test-compile it to find possible errors.
To compile a dataport to test it
Open the dataport in Dataport Designer.
Click Tools, and then click Compile.
This compiles the dataport without saving changes. If the dataport contains errors, it fails to compile, and you are prompted to make the appropriate changes.