Until a preferences dialog is implemented, the only way to change this is to edit ~/Library/Preferences/net.sourceforge.NFSCommander.plist .
Look for the part that says:
<key>confirmAll</key>
<true/>
<key>confirmNetInfo</key>
<true/>
<key>confirmSave</key>
<true/>
Change the true to false to disable the dialogs.

Those are default options, which are active even when not present in NetInfo. They are added for clarity, and to make it easier to change the default behavior.

Not all default options are present at this time, however.

I'm working on putting together an exhaustive list of the default options, but I'm not there yet. When completed, I'll add option dialogs to make it much easier to set behavior.