First you should use IMPORT WIZARD instead. It is easier to use and helps NOT to forget about important commands (like $DEBUG 1) Secondly, don't use $ALLOWNEG - it is only needed for negative prices (which is extremely rare). $OVERWRITE is NOT needed at all, unless you are modifying non-quotation data.
Also you should look into import.log file.
Quite obviously your second data file has incorrect date and this is the reason why data are not imported.
17200201 <--- this is wrong date
Only data starting from January 1st, 1900 can be used and correct date in YYYYMMDD format would look like this 19000101
As I wrote, only dates from January 1st, 1900 are supported. The fact that you can import earlier dates and they would appear in Quote Editor does not mean that they can be used later. They can't. One of many reasons (not the only) is DateNum() function which is returning YYYMMDD format which holds year starting from 1900, so 1900 January 1st is 000101 and there is no room for earlier dates.
I am always wondering why people do that (start debate when there is no debate). You forget the fact that I WROTE the entire program, so I know it much much better than anyone else on planet Earth. So if I say something about AmiBroker it is ultimate answer and there is no "but".