caption appears at wrong slides (captivate 3)

for example, i have a movie with 5 slides. in 4th slide, i add a caption call "web page appears" and at the login button of 4th slide, i put a caption "click the login button". and they should be appearing only at the 4th slides right? however, they appeared at the end of the 3rd slide, with the background of 3rd slide. for example, if the web browser is in blank and i type the address of new webpage, and the new web page appear at 4th slide, the caption however appear on the 3rd slide with blank page. what should i do to make the caption appear at the 4th slide? in editing tab, i put the caption at slide 4 already.please help me fast. by the way, i am using captivate 3.0.1 build 589