A1329W Error

Hi there,

Does anyone know what the error A1329W - Unpredictable instruction (forced user mode transfer with write-back to base) means? This used to be an warning and now it is an error from the assembler. I've been faced this error in LDM/STM instructions, such as:

LDMIA R0!, {R11-R12,R14}^

I've searched in the Keil documention, knowledge base and google but I hadn't success.

Thank you,
Wander.