Autocad only offers a polar and rectangular array on my ADT version. Possibly available in newer versions of AutoCad.

2005 still onyl offers polar and rectangular, but if you have regular points along the poly line you can specify an angle for the array. this will be time consuming, but i don't know of a better way. good luck. let us know what you find

there are workarounds - depending on what you are trying to array.
(i'm the first to admit you shouldn't need workarounds but welcome to autocad)
anyway - you can use "measure" to insert a bunch of seats along an arc or a polyline. just type measure and follow the prompts on the command line. the object you are trying to array should be a block.
another trick is to use the curtain wall function. you can define the units of a curtain wall to be anything you want. parking spaces, dentils on a fascia, etc. then it's simply a matter of insertiing the curtain wall.

Make a block of what you want to array.
Instead of array command, use divide with your block.

norm is right, use 'measure'.

it's a bit hit and miss, i've used it for seating arrangements in a theatre. in my case, i put the insertion point of the block to be 'measured' to the centre rear of the block.

the first block inserted along the polyline ends up at the start point of that polyline, so if i wanted it to be 400mm in (for example) i trimmed the polyline by 400mm, meaning that the first block and all subsequent blocks were in the correct location.

failing that, do it by eye.