I forget about the application token.
My guess is that if you do this to test the button without the refresh, that it will fail.
var text URL = URLRoot() & "db/" & [_DBID_Field_S] & "?act=API_RunImport&ID=10";
$URL
//"javascript:" &
//"$.get('" &
//$URL &
//"',function(){" &
//"location.reload(true);" &
//"});"
//& "void(0);"
So go to your setting for the application, and Advanced Properties and disable the need for application tokens, or else you will have to create an application token and change the first line to
var text URL = URLRoot() & "db/" & [_DBID_Field_S] & "?act=API_RunImport&ID=10"
& "&apptoken= xxxxxxxxxx";
Obviously paste in your app token code where the xxxxxx are.