Why are there different gene expressions that are refered to the same gene in microarray experiments results?
What you are looking at there is a microarray dataset (see the description here).
Microarrays are chips that have many sequence specific probes on them and sometimes they have multiple probes for the same gene.
Readout differences between the probes of the same gene could be caused by either noise in the data or biological effects like expression differences between transcript isoforms - other reasons could be possible as well.