You should have an active DI for that puppy, for a couple of reasons. Mainly, to properly match the output of the onboard pick-up/preamp the bass has. It DOES have a battery-operated active preamp on it, doesn't it?
In the event that it does NOT have a built-in pre (highly unlikely, these days), you might look at outboard preamp/DI units by Highlander, Fishman, and the PreSonus Acousti-Q is pretty nice. But that's if you DON'T already have a pre for the pick-up.
If you DO have that covered, your best bet would be a decent quality DI box by Countryman, Radial, ProCo, Whirlwind, etc. An "active" DI requires a battery or phantom power from the board, and is usually cleaner for bass signals. A "passive" DI utilizes an output transformer( but not any power ) to load the instrument to a board's XLR input. The transformer has its' advantages over an active circuit sometimes, but the transformer tends to be a bit "mushy" on low frequencies, so active is usually preferred for a bass.
The reason you'll want to use a DI box is to permit you to run the signal from the bass to a mixing board without "loading down" the signal and picking up all sorts of noise and interferences. This is especially true if you are running that signal down a 100-foot-long snake to the board.
Active or passive, you'll want to get one of them.

thanks moonbaby, yes, it does have an onboard battery powered preamp. your info is very useful.

do you reckon when gigging (i haven't yet taken this one out) do i need a DI if i'm going through an effects pedal first? i've got a zoom 506 bass effects pedal (like this one http://www.instrumentpro.com/P-ZOO5062.html) -- super cheap but does the job on my other bass -- which i may use.

thanks again....

You would use the DI box after the signal processor, assuming that you will want the processed sound going to the PA. You didn't say in your original post whether you were using a dedicated bass amp onstage, so I assumed not (mistaken?). If you ARE using a bass amp onstage, you would probably want to tap the line out of the amp to do the DI thing. That way, you get the tonal properties of the amp's preamp settings as well.
In either case, be aware that the settings on the processor are going to affect your sound differently going into one PA than they are going to another PA. Parameters like EQ, compression, EQ, distortion, EQ, flanging, EQ, chorusing, even...EQ! They very well may not sound the same through different speakers. Say that you have a small sound system that you've used to set up the presets on your Zoom. Because the bass response is a bit lacking in your system (just as an example, mind you), you've taken the liberty to give the EQ a nice +6dB boost at, say, around 100Hz to fatten it up a bit. Then you hit the stage a week later and plug into a club system with a subwoofer hooked up. WHOA!!! All of a sudden that +6dB at 100Hz is gonna sound like a Harley blew up onstage! Too much of a good thing....Just a gentle reminder..