NT and IIS
Web Crossing verions 3.0 and higher automatically install the DLL preferentially.
The IISAPI module (.dll) file is a direct replacement for the cgi script "webx.exe" which is run whenever a request comes from a user via browser to your Web server. It runs "exactly" like the .exe version, except that it is a .dll and is loaded into the memory space of the MS IIS server rather than being loaded each time a request comes in. It has the same interaction with the main "webxserv.exe" Web Crossing server that the older "webx.exe" cgi program does, sending server variables, etc. and returning the formatted HTML from Web Crossing. However it affords not only a performance increase, but it bypasses the shortcomings of "plain" CGI (whereby the CGI breaks with large posts). If you continue to see problems with enclosure uploading using the DLL, then you need to adjust the Memory Allocated to the Cgi Interface. See here.