NT - NetView 5.1

I have the following problem when I want to collect data in a plaintext
format.
I go to the directory "C:\usr\ov\databases\snmpcollect", and I execute the
command "snmpcdmp file_name" to have the data in a plaintext format, and I
get the following error:

               snmpcdmp: read<ifinoctets.1> failed: <null>

I also have the problem of storing data, because I can only store one day
of data, and I want to store data more time.

Thank you.