Just for the record - since this question came up for me recently - the official answer is that VISA 3.0.1 does support LabVIEW 5.1. In fact it should support any older version of LabVIEW, but that may not be tested/officially supported. See <a href="http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000E9C60000&USEARCHCONTEXT_CATEGORY_0=_201_%24_13_&USEARCHCONTEXT_CATEGORY_S=0&UCATEGORY_0=_201_%24_13_&UCATEGORY_S=0";>here</a>...
