please try to query this OID (126.96.36.199.188.8.131.52.3184.108.40.206.0) on your device using SolarWinds Toolset or SNMP walk utility (http://www.net-snmp.org/)
If this OID doesn't respond or responds with 0, there are some problems with NetFlow configuration through SNMP (e.g. problems with particular IOS)
The good news is that SolarWinds has brand new Free Network Config Generator tool. It's able to configure NetFlow using CLI, not SNMP, so it should work fine in your situation. Please download it here: http://www.solarwinds.com/products/freetools/network_config_generator/
The Catalyst 3560 doesn't support NetFlow at all, so you're not going to have much luck getting it to work...