Most likely, the function "security::safe_tmpfile_p&source_p" fails under windows.
https://openacs.org/api-doc/proc-view?proc=security::safe_tmpfile_p&source_p=1
The definition looks sane to me, it is not obvious, why this should not work under windows. I have no Windows machine around. Raul, can you check, which clause fails in your installation (e.g. adding log statements).
all the best
-g
