Download file from Dropbox to local android Java

Hello Steve,
Thank you for your answer. Actually the program import first the files to the local folder then it open the files. These files are database files.
The program crashes because it cannot find the local files. But this problem occurs only after the first run. I mean if I uninstall the application then I re install, it crashes. But if I just restart after the crash, it works, the local files were downloaded.

Here the error stack trace:
12-31 10:07:46.461: E/AndroidRuntime(24240): FATAL EXCEPTION: main
12-31 10:07:46.461: E/AndroidRuntime(24240): Process: com.wataiso.labnotebook, PID: 24240
12-31 10:07:46.461: E/AndroidRuntime(24240): java.lang.RuntimeException: Unable to resume activity {com.wataiso.labnotebook/com.wataiso.labnotebook.TableauDeBord}: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2791)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2820)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.os.Handler.dispatchMessage(Handler.java:102)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.os.Looper.loop(Looper.java:136)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.ActivityThread.main(ActivityThread.java:5050)
12-31 10:07:46.461: E/AndroidRuntime(24240): at java.lang.reflect.Method.invokeNative(Native Method)
12-31 10:07:46.461: E/AndroidRuntime(24240): at java.lang.reflect.Method.invoke(Method.java:515)
12-31 10:07:46.461: E/AndroidRuntime(24240): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:805)
12-31 10:07:46.461: E/AndroidRuntime(24240): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:621)
12-31 10:07:46.461: E/AndroidRuntime(24240): at dalvik.system.NativeStart.main(Native Method)
12-31 10:07:46.461: E/AndroidRuntime(24240): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.database.AbstractCursor.checkPosition(AbstractCursor.java:426)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
12-31 10:07:46.461: E/AndroidRuntime(24240): at com.wataiso.labnotebook.DatabaseHelper.getInfo(DatabaseHelper.java:477)
12-31 10:07:46.461: E/AndroidRuntime(24240): at com.wataiso.labnotebook.TableauDeBord.showLinkedViewDB(TableauDeBord.java:607)
12-31 10:07:46.461: E/AndroidRuntime(24240): at com.wataiso.labnotebook.TableauDeBord.onResume(TableauDeBord.java:226)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1192)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.Activity.performResume(Activity.java:5310)
12-31 10:07:46.461: E/AndroidRuntime(24240): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2781)
12-31 10:07:46.461: E/AndroidRuntime(24240): ... 10 more