You were almost there. When it comes to literals or strings, you need to single quote them. There are two ways of doing that using variables, depending on whether the assignment is done by LET or SET:
SET vLevelNames='Naam 1','Naam 2','Naam 3','Naam 4','Naam 5','Naam 6'; // This stores as a literal, not evaluating the content, s no need to use & between valuesLET vLevelNames = chr(39) & 'Naam 1' & chr(39) & ',' & chr(39) & 'Naam 2' & chr(39) & ',' & chr(39) & 'Naam 3' & chr(39) & ',' & chr(39) & 'Naam 4' & chr(39) & ',' & chr(39) & 'Naam 5' & chr(39) & ',' & chr(39) & 'Naam 6' & chr(39); // LET does evaluate the assignment, so chr(39) is translated into ' symbol, needed to quote the results in order to get Pick() working
The LET option is cumbersome, but it may be useful in the future when you do need evaluation of the assignment.
Hope that helps