Quoting jimderrico@gmail.com:
> I am trying to change a single field (Priority, doesn't really matter)
> using Change Several bugs at once. The error says:
> You tried to change the Baseline field from dvl3.1_080428_DA to --
> do_not_change-- , but only the assignee or reporter of the SCR, or a
> sufficiently empowered user may change that field.
>
> Our "Baseline" field is a custom field of plain text. I get the error
> running as myself, the reporter, and as bug_admin! It is only
> complaining about that one field (or is that just the FIRST one it
> will be complaining about?). Running version 3.0

Probably first one. Make sure that there is a parameter called
dontchange and it is set to --do_not_change-- in your URL.
(...&dontchange=--do_not_change--...) It is in a hidden input on the
form.

(If you are using IE, it is possible that your URL could be getting
trimmed. IE is known for that problem with long URLs.)