Button Choose file is not working on Android mobile.

Please try first re-embedding your jotform http://www.jotform.me/form/51945955867475 to the website using instead its iframe embed code.

user guide: https://www.jotform.com/help/148-Getting-the-Form-iFrame-Code

Make sure to clear/clean first the previous script code of the form that was use on the website before adding the iframe embed code.

Let us know if this did not fix the issue.

Thanks.