When you have an expression like "([ID] = Forms![Entry Form]![IDLookup])", everything within the quotes becomes a text string. So, Access thinks you want "WHERE [ID] equals the string "Forms![Entry Form]![IDLookup]".
You need to concatenate the value of the control (with appropriate delimiters) to the property.
If [IDLookup] is numeric, then you would use:
Code:
Me.Filter = "[ID] = " & Forms![Entry Form]![IDLookup]
If [IDLookup] is text, then you would use:
Code:
Me.Filter = "[ID] = '" & Forms![Entry Form]![IDLookup] & "'"
Expanded, the text in RED at the end looks like " ' ".