This is on a Catalyst 6500 chassis with a Supervisor 2 module, running IOS 12.1(13)E1, which is a little old. But due to h/w limitations, it can't run much newer hardware. We saw a related article with same errors with a Sup720 running 12.2.18SXF13.
The flows seem to exist on the 6500 when show mls ip flow tcp/udp is issued on the switch, but the data doesn't appear to exist when analyzed with Solarwinds.
Is it an issue on the 6500 configuration, or the Solarwinds analyzer?
Similar issues as on post: Netflow Config On 6509, but different hardware.
There is a great article stickied to the forum on how to setup netflows on a 6500 which is great. Unlike a router it is a multistep process due to the distributed nature of the 6500.
In essence you have to turn on flows for layer 2 and layer 3 traffic.