Hiya - it seems that even when it looks full, the way the reservoir is designed means the salt doesn't feed through very well.... this is what I found with my dishwasher anyway, the salt "sensor" must be further down the pipe...
so just take the reservoir cap off, stick your fingers in and push the salt "around the corner" down the pipe... then fill up with more salt if necessary. should fix it.
Andrew, March 2007