PWS uses wrong PHP version

Hi, this is not a problem with the Win32 version of PHP, but maybe someone here can shed some light ... I have different versions of PHP on one of my machines (Win98SE, PWS4), and whenever a new release comes out, I install the new version in a new directory and change the appropriate entries in php.ini (mainly extension_dir) and the registry (HKLM/Software/Services/W3SVC/Parameters/ScriptMap), and copy php4ts.dll into \windows\system. Lately, I experienced that PWS always seems to use php4.0.4 (located in c:\php\php4.0.4) when a php page is requested from the server. Using a text search I found out that there seems to be a c:\php\php4.0.4-entry in system.dat, that was not shown in regedit. So I used a registry optimizing tool, and now this string is no longer found in system.dat. However, whenever I call a .php page, still 4.0.4 is used. I finally deleted the .php entry in ScriptMap, rebootet - and what do you gess, .php scripts do still get executed. Does anyone have any idea? The workaround - copying the latest distributions in c:\php\php4.0.4 - does work, but I am still very interested why my PWS still executes .php scripts. Where else could I look? Best regards Christian