Hello.
Sometimes control frames that are not understood at one end are seen as input errors.
For example DTP, STP and CDP frames. This could be your problem as I can see you have CDP, DTP and STP on the 2960 but not the 4K.
Try configuring portfast, 'switchport nonegotiate' and no cdp enable on the 2960.
The other thing to check is if the input errors increment at the same amount over the same amount of time? This would indicate the problem to be unknown control traffic then.
Simon