Warning: Because of COMMON...............

I am trying to compile the source code of DRAIN-2DX (an engineering free
software availiable in nisee site).However I am getting 1231 warning
messages of the following type:
Warning: Because of COMMON, the alignment of object is inconsistent with
its type [PKG]
9 FR0(2),CR0(2),FRA(2,2),CRA(2,2),CPIN(2,2),FPIN(2,2),PKG,PKGP,RSum
Can anyone help me with this problem?Although an executable can be created
it does not work.....

.