Writinging issue - 128 bit EPC tag with MC3090-Z

Team,   I managed to  write a tag via RFID API3 Sample3Plus App :
 

IC

NXP U-Code G2iL

Interface Protocoll

EPC Class 1 Gen 2, ISO 18 000-6C

Frequencia

860 – 960 MHz

Memory

128 bit EPC

  But most of the time I receive following error message: Tag not found in the field (but it is there, nearby).

I suspect our demo appl. is not prepared for 128 bit EPC. Because all the new tags store the EPC on 128 bit and I suspect our "writer" manage only 96 bit.

Do you have some information concerning this? Or redirect me to the person who can help?