File download window occuriing when ever play back

Hi experts,

currenly i am working on a project.
for this i need to assign 500users.
before working with 500users, i assigned 10users to check script working fine or not it worked fine.

now i reopened the same script and playback.
it displaying "File download window" last week when i used, i didnt get any window like this.

in the picture script pane starting from
"nca_Set_connect_opt" to "nca_java_action".
for all the 12steps the "file download window is occuring." 12times.