This string taken verbatim gives me a syntax error. The reason is that it uses
UTF-8 double quotation marks ( 342 200 235 and 342 200 234) instead of ascii.
cat tstr.txt text(25, 18, "RWR & SCHH”, “fontsize”, 12, “fontweight”, “bold”); od -c tstr.txt 0000000 t e x t ( 2 5 , 1 8 , " R W 0000020 R & S C H H 342 200 235 , 342 200 234 0000040 f o n t s i z e 342 200 235 , 1 2 , 0000060 342 200 234 f o n t w e i g h t 342 200 0000100 235 , 342 200 234 b o l d 342 200 235 ) ; \n 0000120 \n 0000121
Replacing them with an ASCII (") or single quote (') , gives me the expected