Install4J, the Java installer for moviestorm is just plain shoddy. If the file is truncated (say, due to incomplete download cause by the wrong type of leaves on the line) one of two things will happen. If the file is truncated near the start then it gives a "corrupt download" message. If the file is truncated elsewhere (~>10Mb) the installer starts up, displays a nice bar while it prepares its file and looks great until it throws a "Failed to install AddOn unexpected end of ZLIB input stream." message box. Really - no check for a corrupt download in this day and age?
So I wrote a doofit to verify / validate the install4j binary before it starts copying files. Will punt it up onto sourceforge, but for now here it is.
edit, tis up on sourceforge!