First, you need to make the difference between A and B.
A-You can't add fuel because the fuel tank is full and not indicating properly
B-You can't add fuel because the charcoal canister is clogged, and the gases are not passing through.
To rule out A, go back to your previous thread and do the instrument cluster test (as described by QSilver), to see exactly how much gas you have in your tank. After you know that, you can follow a path...
JOY = BMW