cvs2svn - is dump file platform portable?

While investigating the methods to use when migrating our CVS
repositories from CVS to SVN I converted one of the smaller CVS
respositories to an svn dump file using cvs2svn 2.5.0 on an Ubuntu
Server 16.04.3 machine.

Then I moved the dump file over to the target Windows 2016 Server
where I had just installed VisualSVN and tried to use the VisualSVN
GUI tool to load the dump into a new repository. But it threw an error
box displaying:
"Could not convert ' 2' into a number"

Next I tried to load it from the command line:

svnadmin load \SVNREPOS\bosse < bosse-dump
' into a number04: Could not convert ' 2

Strange output and it stopped. Same basic error...

Then I went back to the Ubuntu machine and loaded the dump file into
svn there and it worked just fine.

So I made a dump from the newly loaded repository on Ubuntu and went
back to Windows 2016 and repeated the load command with the new dump
file.
This time it worked without errors!

So my question is:
Is the dump file format from cvs2svn platform dependent such that it
will not work if moved from Linux to load it on Windows?

It seems like dump files from svn itself work when moved between
platforms.
(Both systems have svn 1.9.7)

-- 
Bo Berglund
Developer in Sweden