I think I know what it is However please state the problem in a clearer way, e.g. refer the function by name (a few of us don't use C-), copy the exact error message you see, etc

cider-load-buffer is the function and the error message is

cider-load-buffer: Buffer '*cider-scratch*' is not associated with a file

Ok, at first I thought it was a sesman issue, but that's not it this helper essentially calls the nrepl "load-file" op. Its doc is:

:doc "Loads a body of code, using supplied path and filename info to set source file and line number metadata. Delegates to underlying \"eval\" middleware/handler."
:requires {"file" "Full contents of a file of code."}
:optional (merge caught/wrap-caught-optional-arguments
                 print/wrap-print-optional-arguments
                 {"file-path" "Source-path-relative path of the source file, e.g. clojure/java/io.clj"
                  "file-name" "Name of source file, e.g. io.clj"})

I'd suggest, jump to cider-load-buffer and play with it, you essentially want to:

(cider-request:load-file (buffer-string) blah blah)

(bear in mind that if you load code this way, stacktraces, jump-to-def, etc will be less functional)