The w32inst.dll module is used by the wtvdr22.exe program which is the actual driver for the soundcard. It then installs the Sound Card into the Windows operating systems. The soundcard driver can also serve as update for Creative Labs Sound Card drivers installed on computer systems that use Win9x. The driver is not compatible with the Windows XP operating system, which might be the reason you are getting the error message.
In very odd cases, the w32inst.dll is related to Complete Professional Whitening Kits. When this is the case, it is because of spyware and the file needs to be removed immediately.
SpeedZooka runs on Windows XP, Vista, 7 and 8. It has no ads, popups or bundled software and fully uninstalls by clicking Start > All Programs > select SpeedZooka and click Uninstall.