Alan, T2 is defined by Stephane as a 16 bit sfr, the concatenated TH2:TL2. Whether Keil can handle this or not, I don't know.

I would recommend against trying to access a timer when it is running. To get an accurate answer would require three 8 bit reads (read TH2, read TL2, re-read TH2 to see if it has changed), or else you must stop the timer, read it, and restart it.

Stephane, I believe you will want to copy the 16 bit value you get from T2 (however you get it) into a regular u16 variable. Keil evidently has a problem doing arithmetic against an sfr.