Rtx51-tiny REQUIRES UPGRADE to PK51 error log _tiny

1. The question

When using the RTX-51 real-time operating system, a compilation error occurs, as follows:
* * FATAL ERROR l257:rtx51-tiny REQUIRES UPGRADE to Pk51*

Rtx51-tiny requires PK51 's permission.

2. Ways to Solve

Search on the internet for a long time, the solution is mostly, re-import license, but I have imported many times can not solve this problem.

Later, there is no way to download a version of the Keil51 to install, use the Registrar that shipped with this installation package to register without errors.
So compared to the previous use of the registration machine, are two different kinds of software. Screenshot below:

In addition to the choice between the two are a mother born, so did not say that there are two registers, I really do not know how it is.