Since no one has ventured an answer to you, maybe I'll give it a try.  As
the HP3000 comes "out of the box" it does not have a standard file
transfer program.  Many sites use the WR&Q product Reflection for termial
emulation.  It supplies a (its own proprietary) file transfer program.
 
It may be possible to locate a version of Kermit.  I am aware of one that
has been written for the HP3000.  (That one is supplied by Vesoft when
you purchase either their MPEX or Security products.)
 
If you have version 5.x of MPE (and a C compiler), you may be able to
find the source code to one of the standard file transfer programs
(intended for Unix) and port it to the HP3000.
 
Any finally, if your PC and the HP3000 are networked, and the HP3000 is
on version 5.x of MPE, you could use FTP to transfer files (if you have
ftp on the PC).
 
Hope this gives you some help