c# - Add Key to appsettings in web.config shows An error occurred loading a configuration file: Access to the path 'c:\inetpub\vobv5_zi.tmp' is denied -

i trying add appsettings in web.config in c://inetpub folder. getting error error occurred loading configuration file: access path 'c:\inetpub\vobv5_zi.tmp' denied. (c:\inetpub\web.config.config)

here code

in vb

dim config configuration = configurationmanager.openexeconfiguration("c:\inetpub\" & sserver & "\web.config")         config.appsettings.settings.add(ssearch, "c:\attachments\")         config.save(configurationsavemode.modified)         configurationmanager.refreshsection("appsettings") 

in c#

   var config = configurationmanager.openexeconfiguration("c:\\inetpub\\web.config");         config.appsettings.settings.add("os", "linux");         config.save(configurationsavemode.modified); 

i tried in both vb , c# . when web.config in project adding appsettings while web.config in inetpub throwing error error occurred loading configuration file: access path 'c:\inetpub\yzb2crt2.tmp' denied.

the user running code (not quite clear how running code) needs have write permissions on file.

seems pretty clear perhaps there more information might need give us?