TStringList causing compilation error in HE4 (SOLVED)

I am having trouble with some scripts that used to work with HE v3.6 but are failing with HE v4.02. These scripts will “Check” and “Save” OK but fail to compile with error messages like:

Fatal compilation error
Unknown identifier or variable not declared: ‘TStringList’.
Source position 7,20

This happens even with this simple test script taken from the HE documentation

function ReadTextFile(Filename: String): String;
T: TStringList;
EbookPath: String;
T := TStringList.Create;
EbookPath := GetGlobalVar(“HEPublicationPath”, “”);
// Loads the text file.
T.LoadFromFile(EbookPath + Filename);
// Gets the contents.
Result := T.Text;

Comments/fixes apppreciated.

Sorry - I think I’ve discovered the solution in the HE4 documenation. Have to put “uses Classes;” at the top of script.