Startup error - ora-32004

Dear Sir,

I am using HP server with 8 GB RAM having 4 dual core processor, runing 32 bit windows 2003 server sp2 and Oracle DB 11g in archive mode.  For the past 10 months I was running DB with SGA 720MB.  Enterprise Manger recommended to user SGA to 900 MB.  Therefore I excuted the following Script.

ALTER SYSTEM SET SGA_TARGET=900M scope=spfile
alter system set sga_max_size = 900M scope=spfile;

On restarting the database I am getting the following error.

ora-32004 obsolete and or deprecated parameters specified.

I ran the following SQL, and no rows are return

select name, isspecified from v$obsolete_parameter where isspecified='TRUE'