Hello there. I have had some experience with that type of dimmer, and before you go thru the expense of replacing it, there are a few things to look at:
1: Check all wiring and terminations, especially at the dimmer. These types of dimmer can run quite hot, and it may be as simple as a burned or loose connection.
2: These dimmers have a movable contact or brush if you will, it can usually be replaced without too much trouble. Get the brand and model and serial numbers off of it and you can usually find replacement contact brushes.
But be aware that it is possible that if the brush was wearing out, it could have arced up the windings were it makes contact. If that is the case the dimmer is not repairable. A new brush would simply continue to arc as it hits the bad spots.
It is remotely possible that it has completely burned up, in that case replacement is the only option.
Economical replacements..depends on the total load connected but a dimmer of suitable grade for commercial use will not be cheap.
Please post back with all the info on the dimmer and total connected load, get pics of it if possible..I may be able to steer you to a suitable replacement.