Datawindow error: ct_send() :user api layer error: this routine cannot be called because another command structure has result pending

Dear all,

when I retrieve datawindow in client PC. I always get this error as below. But the strange thing is some user got this error and the others works well.

So I don't understand what wrong with them. And I install sybase client 12.5.4 on every client PC to connect sybase. Thanks in advance

Sybase 12.5.4