Name Does not Match

i just got an email from ecfmg saying that the name on my medical school diploma does not match the name on the application.
when i re checked there is a space in my last name that is not present on my medical diploma..
they asked to re send my application..
what does this mean
how should i proceed
i only need to correct the spelling of my last name ( remove a space) on the ecfmg application
please help