Problems with Stored Procedure in AIX and informix 9.4

Hi All, i have an AIX operating system version 5 and informix 9.40 UC3 running on it. I am running a stored procedure as user "aa" who has an execute permission. The stored procedure calls a SYSTEM command --> "SYSTEM env". When this command is run from a stored procedure then the value in "INFORMIXSERVER" is something else which is not set anywhere. For Example, When i run from $ prompt as "env | grep 'INFORMIXSERVER' ", I get the value of INFORMIXSERVER as 'x' But when I run the same "env" command from within a stored procedure as "SYSTEM env", I get the value of "INFORMIXSERVER" as 'y'. This value 'y' is not set anywhere. Has anybody gone through this type of a problem and if yes....then what is the solution. Thanks and Regards Vaidyanathan