I think it only works with Flash CS5.5. Looks like in 5.5 they've implemented new JSFL command : "fl.getDocumentDOM().getSizeReportXML" that doesn't exist in previous versions.. Which is quite sad for us since we we have version 5 and would have to fork out 550 bucks for an .5 upgrade upgrade that should realy be free .
I get an error in extension manager when trying to install "The extension package is invalid. The extension will not be installed." I have Flash Pro CS 5.5 and Extension Manager CS 5.5. I am running on WinXP.
Since the Extension Manager is prompting that "The extension package is invalid.", please make sure that you have fully downloaded the package. Size should be 589.512 bytes (see properties of visualsize_report_p1_09211.zip). Let us know if this solved the problem.
Apparently your file extension has been changed somehow to *.mxp?! Should be *.zxp. (Note: we reproduced your error message by renaming the package's ending to mxp)
Please let me know if this solves the problem.