When I try to use mailx on AIX 5.2 I get the following message:
"The flags you gave make no sense since you're not sending mail."
The type of command sent is as follows:
mailx -s "Test" -c gilstanden@hotmail.com < sendmail.pid
but it just gives the message referenced previously.
Do I need to configure something in the sendmail.cf file ?

You need to to have a "to address". You only have a "cc address". mailx regards that as illegal although I think that strict reading of the rfc's would indicate that it's acceptable. Simply removeing the -c should be enough to get it to work.