RC153710631CN my parcel shows location PEK and activity NULL what does this mean?

As by the FAQ stated above:

I track my parcel at China Post, but it shows NULL. What does it mean?
Answer: The English information on the official website of China Post is translated from Chinese tracking status, but not all information can be successfully translated. So “NULL” is a technical problem of the website, not your parcel. TCG’s tracking tool borrows the original Chinese status and translates them into simple and understandable English terms.

I found the location of PVG/PEK/FOC/CAN when tracking my package. What do these initials refer to?
Answer: These are the ITIT codes for airports. PVG refers to Shanghai Pudong Airport. PEK refers to Beijing Capital International Airport. FOC is the ITIT code for Fuzhou Changle International Airport. CAN is the airport code for Guangzhou Baiyun International Airport.

Hi, Gina.
What Hugo said was right. The PEK means the beijing airport.
I helped you to check the latest status and found it as "2014-01-20 17:59, International reception, -, LISBOA,", so I think you will get your parcel soon.

Thanks for your help.