Olimex ARM-USB-OCD-H with LPC-P1114 and LPC-P1227 boards questions
I think the answer is that you cannot program these processors using the ARM-USB-OCD-H, at least not with OpenOCD. The important point is that the LPC11xx processors require a Single-Wire Debug (SWD) interface rather than JTAG, and I suspect that the LPC12xx have the same requirement. Olimex sells an SWD adapter for the ARM-USB-OCD-H but the web site indicates that is only works with Rowley Crossworks.

You might look at using an LPC-Link. You can cut an LPCXpresso board in half and use the programmer separately from the target, and I think there is support for using it with gdb.