odd linux mplex problem

[derek_nolan@y...]

So I can successfully use ExtractStream to get .m2a and .m2v files
onto my linux PC (via NFS). Once there, I try to run mplex on them.
I've tried all sorts of variations of the mplex -f option, so that
doesn't seem to be the problem. In the directory, I have:

[root@f... wsop]# ls -la
total 2635632
drwxr-xr-x 2 65534 65534 4096 Sep 4 10:30 .
drwxrwxrwx 5 root root 4096 Sep 4 13:08 ..
-r-xr-xr-x 1 root root 86346432 Sep 4 13:32 wsop.m2a
-r-xr-xr-x 1 root root 2609881898 Sep 4 13:32 wsop.m2v
[root@f... wsop]# 

When I run mplex, I get the following:

[root@f... wsop]# mplex -f 4 -m 2 -v 2 -o wsop.mpeg2 wsop.m2a
wsop.m2v
INFO: mplex version 1.4.1 (7.12.2000)
**ERROR: File wsop.m2v not found.

The file is definitely there, and readable by root. I'm wondering if
there is some kind of size limitation? Any help would be much
appreciated.

Thanks... 

Derek