Thank you !
It first tells me an important thing: you are using the Windows build (Linux and Windows fonts processing are quite different, even when both are using Freetype as the font renderer as it is the case for the viewer). I updated Freetype to v2.10.4 for next builds, but since LL is still using a totally outdated (and security holes riddled) v2.4.4, I doubt it will make any difference for Windows builds...
From the log, I also can see that the default v1 viewers fonts get loaded (and not the Roboto ones, like I hinted you to try with)... Is the log matching a sessions for which you did (try and) replace the default fonts for Roboto ones ? If the answer is yes, then you obviously did not manage to change the font.
Now, another issue could be that, since v3+ viewers are now all using the DejaVu fonts, which got a much wider characters set as even the Roboto ones, some super-silly UTF-8 characters could still be seen with those viewers and not in mine... Here is a zip file containing DejaVu fonts and a patched fonts.xml file: simply copy the contents of the fonts directory (i.e. the three *.ttf files) of the zip file into the fonts\ sub-directory of the viewer installation directory, and the skins directory itself (i.e. skins\ and all its sub-directories and files) into the "%AppData%\SecondLife\" directory (this will expand to "C:\Users\tomik\AppData\Roaming\SecondLife\" in your case, from what I can see in the log).
EDIT: zip file attachment removed since no more needed with v1.28.2.28 and newer (see the message below).