I can't say I've ever experienced that. I'm running FS9 also, on Win7 with the latest update of FSUIPC (Ver 3.98). As far as I know, (& perhaps you do too), the file only works properly when the other default .dll file is removed from the FS
modules folder, otherwise a 'conflict' error message comes up on sim start. Are you using the WideFS version or the standard FS2004?
Worst care scenario, it may be a great idea to contact Peter directly for some assistance, or check out the forums: http://www.schiratti.com/dowson.html