HP 6120g/xg blade switch connect problem

[Gaurav_ASE]

We have a loop problem in HP 3com 5500 and blade server switches 6120xg.

In Current scenario, we have two HP 3 com 5500 HI switches which are working as virtual one core switch as IRF is enabled and we have two Procurve 6120xg switches in blade server.

Problem:- Both 6120xg are connected with 2 HP 3com switches 10g port and we connected both 6120xg together with UTP and found loop in both 6120x switches even STP is already enabled. So kindly check the issue.

the question is:- if core switches are coneected with both 6120g/xg switches with fiber and if i can connect utp link in between both 6120g/xg switches then stp should block 2 link but its not happing here ..stp is enabled and loop is affecting network. i just want to know any slotuion is .

i want to connect both 6120g/xg switches together or there is any internal link so i can use for connection.