[Therion] Explored 80m OK, 8m not OK

Hi ya In my th file the line station RO31 "cream-brown flowstone too nice to explore" \ continuation explored 8m attr code "explored 8m cream-brown flowstone too nice go further" gives the following error; D:\Program Files\Therion\therion.exe: error -- SurveyRO.th [250] -- invalid explored length specification -- 8m Whereas the almost identical line (80m in place of 8m) station RO31 "cream-brown flowstone too nice to explore" \ continuation explored 80m attr code "explored 8m cream-brown flowstone too nice go further" compiles perfectly. What is going on? Am using 5.2.3 Regards Bruce