With a newer version of
biblatex the first error I get from your example is slightly more helpful than the errors shown in your screenshot.
! Package biblatex Error: Incompatible package 'natbib'.
See the biblatex package documentation for explanation.
Type H <return> for immediate help.
natbib for citations and the bibliography. (The example file then proceeds to add the references manually in
thebibliography and does not provide any author-year metadata in a
natbib-readable format, so the class does not make use of many of
natbib's most valued functions, but the package is still loaded.)
biblatex are completely incompatible and can not be used together in the same document. Since your template loads
natbib, the viable option is to stop using
biblatex. Indeed, not a lot of publishers are known for accepting
biblatex submissions and
biblatex usually requires a different workflow (Biblatex: submitting to a journal).
In the example it should be enough to drop
biblatex to make it work again (assuming you have the file