help for execute immediate

hi i am writing a new stored procedure. the error i am gettin g is i have a variable whereclause
in this i have an and clause as

whereclause := ' AND usr.act_key IN (SELECT DISTINCT act2.act_key FROM' ||

	    	                                        ' act act2, aad, usg,
ugp, usr usr5'     ||
	    	                                        ' WHERE usr5.act_key =
aad.act_key'      ||
	    	                                        ' and aad.ugp_key    =
usg.ugp_key'      ||
	    	                                        ' and ugp.ugp_key    =
usg.ugp_key'      ||
	    	                                        ' and usg.usr_key    = '
||
                                                        ' intuserkey_in

in am using the same in my execute immediate statement but not getting the desired result

  EXECUTE IMMEDIATE 'SELECT count(*)'

||' FROM usr,'

		 ||      ' act,'
		 ||      ' oiu,'
		 ||      ' obi,'
		 ||      ' obj,'
		 ||      ' ugp,'
		 ||      ' usg,'
		 ||      ' aad,'
		 ||      ' oug'


		 ||' WHERE  usr.act_key = act.act_key'

		 ||' AND    usr.usr_key = oiu.usr_key'

		 ||' AND    oiu.obi_key = obi.obi_key'

		 ||' AND    obi.obj_key = obj.obj_key'

		 ||' AND    usg.usr_key = usr.usr_key'

		 ||' AND    usg.ugp_key = ugp.ugp_key'

		 ||' AND    aad.act_key = act.act_key'

		 ||' AND    aad.ugp_key = ugp.ugp_key'

		 ||' AND    obj.obj_key = oug.obj_key'

		 ||' AND    oug.ugp_key = ugp.ugp_key'

                 || whereclause
                 INTO inttotalrows_out;

the problem is whereclause variable is not getting appended to
statement

can any body help