求救，快照问题

catno8

>;     1：在wxp上建立公用dblink，正常，dblink也可用
create public database link mylink connect to scott identified by tiger using 'center'
>;     2： 在center机子上建立快照日志，正常
create snapshot log on emp with primary key
>;     3： 在wxp机子上建立快照
create snapshot emp_shot build immediate refresh fast next sysdate + 1/2880 as select * from emp@mylink
>;     出错，提示：ORA-12014: 表'EMP'不包含主关键字约束条件
>;     
>;     表'EMP'上有主键，不知道为何报这个错，若无主键建立快照日志时也报这样的错误
我查看了所有有关ORA-12014的错误信息
ORA-12014: table 'string' does not contain a primary key constraint
Cause: The CREATE MATERIALIZED VIEW LOG command was issued with the WITH PRIMARY KEY option and the master table did not contain a primary key constraint or the constraint was disabled.
Action: Reissue the command using only the WITH ROWID option, create a primary key constraint on the master table, or enable an existing primary key constraint.
在emp表上有主键，并且是可用的，实在是找不出原因，请高手指教

pearaep

把主键信息贴出来看看