Today while taking a shot at vista IIS 7.5 and I was attempting to erase one of module named as CustomErrorModule for Default Web Site and quick I was informed with this decent lapse.

Also this appear to be occurring just with Modules which are recorded as Native. I had the capacity erase Managed module without any problem.nothing was accounted for under framework & application occasion viewer logs. Arrangement was to go at Root level Modules designs and select the required native module and Unlock it.

The  IIS 7.5 Native Modules seem to be locked by default and same would be valid incase of appcmd tool.

C:\Windows\System32\inetsrv>appcmd unlock config /section:httpErrors
Unlocked section "system.webServer/httpErrors" at configuration path "MACHINE/WEBROOT/APPHOST".

Happy Coding!