raster resampling error

Check that particular clipper polygon, I bet it's really narrow so that you end up with less than one pixel for one of the raster dimensions after your resampling. In order to avoid this you'll need to enforce a minimum size for the clipper features.

Or it's a larger clipper polygon that just gets the edge of the raster. Get the properties of the features coming from the raster port and discard any where num of columns or num of rows = 0

Or it's a larger polygon that just gets the edge of the raster. Get the properties of the features coming from the raster port and discard any where num of columns or num of rows = 0

That could be possible...

I'm merging the tiles before the clipper now.

But if that fails I'll try to discard the ones with columns or rows = 0.

Where can I find the attribute columns or rows so I can use the tester transformer.

You could throw in a RasterPropertyExtractor after the Clipper, to get the number of rows/columns, then use a Tester to filter out those with a zero for either value. It would help to debug the issue and also let the workspace run to completion without those features.

Which is pretty much what @ebygomm said - I really ought to read other answers more closely before posting myself!

Great minds think alike and fools seldom differ :-)