How to address ORA-22813 ?

One of our application user is saying, he got this error when trying to get the ouput using collections !?
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*oerr ora 22813

22813, 00000, "operand value exceeds system limits"

// *Cause:  Object or Collection value was too large. The size of the value
//          might have exceeded 30k in a SORT context, or the size might be
//          too big for available memory.
// *Action:  Choose another value and retry the operation.

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pga_aggregate_target value is set to 250MB and the DB version is 9.2.0.2

Regards,

Jay

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