Here is the list of valid error-reason strings:
Missing Parameters : whenever app-path and bind-path are not specified.
“Stub Start Error” : unable to start the stub for various reasons like fork failure, bind error, listen error.
“Stub Connection Failure” : client socket creation or connect failure.
“No Permission” : stub executable has no exec permission, stat failure, and so on.
“Stub Request Handling Error” : unable to send the request to stub, received invalid/no response from the stub for a request, and so on.
“Set Parameter Failure” : when set user, group, chroot, nice (and so on) fail.
“Invalid user and/or group” : when user and/or group is invalid.
“Invalid Parameters” : when invalid nice value is specified.
“Server Process Creation Failure” : application fork failure, application exec failure, bind error, listen error, and so on.
“Fastcgi Protocol Error” : invlid record version, invalid record type, unkown role, and so on.
“Internal Error” : unable to open the file to be sent to the filter application, any other unknown errors.