Yes. Presuming you're working as freelancer. Without a doubt. Regardless of how much you're being paid, or if you're not being paid (such as if you work with models). If you're employed rather than freelance then the company's existing insurances will probably protect you, but make sure to check.
Professional indemnity insurance protects you from any claims of inadequate service to the client.
Public liability insurance should be purchased as well in case someone injures themself and it's considered your fault. Such as if someone trips over your camera bag, or a lightstand falls on them and they try to sue.
These insurances will provide cover for the legal costs and expenses in your defence as well as compensation payable if they win any payout. They can be picked up alongside equipment insurance (Photoguard and Aaduki are two commonly seen names).
At the same time I recommend getting your camera gear insured as well if it isn't already. Depending on the gig of course, the last thing you want is someone spilling a drink and you have to foot the repair bill or buy new equipment to replace it.