:

[orbisvicis]

Problem:

Command 'vimppm' already exists, Not replacing existing command. Use ! to override.

Fix:

Change:

commands.addUserCommand(..., ..., ..., ...)

to

commands.addUserCommand(..., ..., ..., ..., true)
`

[cd01]

I guess that your vimperator load vimppm.js twice.
Normally, vimppm.js is not only once at startup of vimperator.