Error description in IMM 5257 form

[haritamanna]

I've been getting this msg upon uploading my complete and validated form,

'Error: We couldn't upload your file.

• Error Description:
  Make sure you are using the latest application form from our website. You can get it by clicking on the link below.
  • Answer all questions on the form
  • Click on the validation button
  • Save it on your computer (as a PDF)
  • Upload the saved PDF document here'

I am able to upload everything but this. Please do help.