When I am creating access sequence, the system gives a message, "the table is cross-client".
What do you mean by this message?
Cross client tables in sense, you will not define the tables independently in DEV, QAS & PROD servers. You define them in DEV & then transport them into QAS & PROD. When access sequence is created, table sequence will also be transported into other servers. Which means that DEV & QAS cannot have different table search sequence.
System just tells you that if you make any changes in cross client tables, then you need to keep in mind that changes will flow into QAS & PROD.