This is strange but sure we can find a solution.
May be this is a problem with the installation and conflicts with older versions, but in that case you would have problems in the loading/unloading process, not in the analisys of the scene. (but windows is misterious, there could be a lot of causes). Anyway if you have SWmaxwell2005 it has an uninstaller, but in swMaxwell it is not needed, check you have the last version, delete the older swmaxwell2006 and replace it with the new one (do not overwrite, first delete and then replace, ok? )
But as I say, I am not very sure this is your problem. First of all I need to know when SW crashes. Please check if the mxs file is written before the crash. isn't it? The last instruction in the scene analisys is a call to the mxcl command (which launches maxwell app) and I had to change this call in the last release of the plugin for some reasons. Just before this call, the mxs is written so if you have this file in the right path, we know where the program crashes. This call depends on several settings of your system and it would explain why we have not seen this in other computers.
If you have not the mxs file then the problem is a bit more complex. Get a big assembly, do not apply any maxwell material, and press the render button. You will see the percentage of the process in the status bar below. does the crash happen when the status show 0%, 100% or a middle value?
With this info I can send you different versions of the plugin with some functions disabled (i.e. without sky, without textures, ...) and we can check the origin of the problem. But I think that with the first steps we are going to get info enough to fix this issue very soon, sure today. Sorry for the inconveniences.
PS. I have compiled a new version of the plugin with some of the suggestions of Eric (Thanks Eric

Thanks for your suggestions,

Juan