Couple of things here :

• Like others have posted, seperate the executable, for it is useless for non-win32 users, yet it's 2.2M.
• I would like to see more coloring, like variables, brackets, parens etc.
• Also I'd like to note that the comments (gray) are barely readable due to the background. It'd be cool to be able to set the colors yourself. And I find the choice of red for print commands quite odd, but that's all personal preference. (I see red as an error)
• When/if you implent the color preference choose dialog, please include an option to change the font size too, for I find it quite big.
• I wondered why my scripts were "not recognized as a valid Perl script", when pressing the "Run Script!" button, but the source showed me that's because I (almost) never use a .pl extension. Why did you choose for such a test?