NOD32 does have that problem, though it does block me from accessing my modem configuration in Internet Explorer and Firefox, I can only access it via Explorer . To fix it I have to turn off NOD32. Nodem is a D-Link DSL 502T. The error I get says: Content Length 402.
I do not think it is NOD32's problem. NOD32 does not attach to IEXPLORER or FIREFOX so it should not affect it...
Do you have your browser set to higher compatibility or higher efficiency mode? If the latter, try switching it to HC mode.
Just so I understand the situation... Your modem is an external DSL modem. You access the configuration page using a web browser. However, when you try to do so, you get the "Content Length 402" error. Doing a Google search on Content Length 402, it appears that this is not an error message, but part of some webpage code that does not get processed correctly. Try Marcos's suggestion. Go to IMON --> Setup --> HTTP --> Compatability setup --> Server compatability. Add the IP address of your D-Link modem and see if this fixes your problem.