Sorry for the question if it has been asked and answered already, but do you need both Script Editor and Script Debugger? I have downloaded the demo for SdB 3.0 and before I purchase I wanted to know what am I getting that is not in the SE 2.0 beta. Another reason I ask is that I notice that when I have an error in SE 2.0, it doesn’t highlight the line where the error occurred like the previous versions of the Script Editor did.
No, you do not need both. Script Debugger offers dozens of features that SE does not (and never will). There are so many SD features that to try to list them all would likely take hours. If you plan to do more than casual scripting, SD is well worth the investment.
Disclaimer: bla bla Not Affiliated bla bla Very Happy Customer bla bla. 
I don’t have any idea why Script Editor 2 doesn’t highlight the error. Due to its beta status, maybe this is a known bug.
Thanks for your quick response1
Since you are new to scripting, and since ScriptDebugger is a fairly advanced editor and AS environment debugger, you might really find good use from the free Smile, which is a script editor/debugger.
Smile is a very robust, well-liked and easy to use script editor, with a ton of features and a great new manual.
You can download Smile (I am not affiliated, other than by marriage) from their Smile download page, which is: http://www.satimage.fr/software/en/soft9.html
HTH