No, it's something between the OECD and Avast. Disabling scanning of OECD solves the problem, while disabling scanning of C-Dilla makes no difference.
This is what I did (thanks to OECD support):
[1] Right-click on "avast" icon in taskbar.
[2] Choose ON-ACCESS PROTECTION CONTROL from the menu.
[3] Click the DETAILS button. On the left hand side, click the STANDARD SHIELD icon.
[4] Click the CUSTOMIZE... button, ADVANCED tab.
[5] At the bottom of this screen, add a location to exclude from
scanning by clicking the ADD button. Type in the path where the OED is
installed. (By default it is C:\PROGRA~1\OED\*.*, but foreign language versions may use another name for Progam Files. Note that you must use the short filename for the PROGRAM FILES folder.) Click OK.
My OECD is now functioning normally.
