Answer:
The viewer versions for RFEM 5 and RSTAB 8 are nothing more than full versions that are limited in their functionality.
RFEM 5 and RSTAB 8 are designed for the x86 processor architecture that is used in the majority of desktop computers and notebooks. Tablets are based on a different processor architecture (ARM) and operating system.
However, there is an option to use the Viewer. To do this, you would need to install Remote Desktop Client (for example, from Microsoft) on your tablet. This allows for remote control of your office computer via the tablet.