Well, this may not be such a rare event indeed;
I am deriving this result from the solution! After doing many things to solve the problem, ( actually my number one suspect were network adjustments at the control panel, I have the habit of playing with everything at my computer ) I finally did two more things;
1) I made a deep clean at my computer, with Windows 7 64 Bits's and IE 9's own tools, and CCleaner. And then I uninstalled Comodo, both from the Control Panel then with its own community prepared uninstallation tool, rebooting many times, and deleting many times. I even used Registry Seeker just to delete " comodo " name from everywhere at the registry.
2) Then I resetted IE9. From tools-internet options-advanced-I used both of the two tools here.
rebooted, and it was gone!
I reinstalled Comodo.
I now have one _avast_ folder in Temp, and one _avast_ folder in Temp-Low ...But now no temporary file is produced, both of these _avast_ folders are empty since one day!