procmail cannot read ~/.procmailrc

I installed procmail as the default mail delivery agent
on IBM AIX 4.3.2 with sendmail 8.9.1a.

Procmail doesn't read ~/.procmailrc of users.
With log enabled I obtain the following errors:

procmail: Couldn't read "/somedir/otherdir/$HOME/.procmailrc"

/somedir/otherdir is the correct home-dir of the users.

I tried to change the definition of the path of ".procmailrc" 
in config.h from

        #define PROCMAILRC      "$HOME/.procmailrc" 

to
        #define PROCMAILRC      ".procmailrc"

and I obtain the following errors:

procmail: Couldn't read ".procmailrc" (correctly)

Anyone has an idea of the reason of bad substitution?

Thank's in advance

Alberto Brosich
System Manager
University of Trieste
Italy