prosthechea prismatocarpa, pseudobulbs shrivelling

[headbanger333]

Hello all,
I was given a lovely prosthechea in bloom last year and was told they need a two month dormancy in winter, no water. It has had its water withdrawn with the resultant withering of the bulbs which were smooth and shiny when I received it last summer. Have I done the wrong thing? I am fearful of ignoring the advice I was given by its previous owner because it was in great condition when I got it.