Hides the block even if it is not "empty".
Is somewhat an opposite to touchBlock().
Consider a block (a 'edit' link for example) that should be visible to registered/"special" users only, but its visibility is triggered by some little 'id' field passed in a large array into setVariable(). You can either carefully juggle your variables to prevent the block from appearing (a fragile solution) or simply call hideBlock()
Table 47-1. Possible PEAR_Error values
|Error code||Error message||Reason||Solution|
|SIGMA_BLOCK_NOT_FOUND||Cannot find block '$block'||There is no block $block in the template||Check the block name spelling, check whether you added all the necessary blocks to the template|