assembly - mate problem

Hi all

   I have two parts, one table and the other one is kind of cylinder which is supposed to move along the table. The cylinder moves but the problem is that after inserting the parts into assembly I can not move the cylinder anymore. I attached both part and assembly you can see the difference. I would be thankful If some one let me know what is wrong with my assembly. How can I move the cylinder after inserting into assembly?

Thanks.

SolidworksAssemblies