Just because you didn't generate any errors in creating the MXP file doesn't mean your extension is ready for sharing. There's many a slip twixt the cup and the happy, stable cross-platform user experience. Be sure to test your packaged-up extension before inflicting it on unsuspecting users. The basic tests performed by the quality control techs at the Macromedia Exchange are a good model for testing. These tests include the following:
Does the extension install correctly? Try your MXP installer file out, on both Macintosh and Windows platforms if possible. Make sure all the files get installed in all the proper places, and that all configuration changes are successfully made, as well. (Note that, if you're installing onto the same copy of Dreamweaver where you developed your extension, you'll want to manually remove the development files from your Configuration folder before installing.)
Does the installed extension work properly? Presumably, at this stage of development you've already done your error checking (see Appendix D, "Submitting Extensions to the Macromedia Dreamweaver Exchange," for advice on this). But does the installed extension work the same as the development version you created? Does it work cross-platform? Does it disturb any of the functionality of other Dreamweaver extensions, including other third-party extensions?
Is the installer file (the MXP) virus-free? Although this has nothing to do with the inherent quality, stability or usefulness of the extension, you'll certainly affect the user experience if you pass a virus along with it.
An extension that passes these tests qualifies for basic approval at the Macromedia Exchange. See Appendix B, "Macromedia User Interface Guidelines," for information on user interface guidelines, if you want your extension to qualify as a Macromedia Approved extension. More information on both of these topics is available online at the Exchange.