"Is it just a problem with a hard disk or should i rebuild the vDisk?All data is lost?"
If your host can still view the LUN and access files, the data is not lost. Generally arrays do not worry so much about what is actually on the disk - but that the status of the vdisk/volume is OK.
FRU - field replaceable unit - so it looks like a disk has a problem. You may need to replace it. Did you only see that event once? Is the disk listed as failed or something in the SMU?
