hello, 
i just launched my task and received some complaints that the "continue" button (i.e. the next button) is appearing as strange symbols. i don't see this from my end while using a mac (macOS High Sierra), but do you have an idea of what could be causing this/how to fix it? 
thank you!

Could you please link to the script and, if possible, describe the "strange symbols"?

again, i do not see the "strange symbols" myself, and the participants didn't specify anything further. i am attaching the script with the relevant files, thank you so much!

Thanks for the script -- I am not seeing any strange symbols either (tested under Windows, too), so I have no good idea what the underlying issue could be / why (some?) of your participants are seeing something else. One thing you *could* try is to explicitly specify the text that should appear on the "continue" button, by defining the /nextabel and /finishlabel attributes in your <survey>. Speculating a bit, perhaps it is a font issue, so you could specify a different font as well.

<survey check>
/ nextlabel = "Continue >>"
/ finishlabel = "Continue >>"
/ navigationbuttonfontstyle = ("Arial", 2%)
/ pages = [1=questions]
/ responsefontstyle = ("Arial", 25)
/ itemfontstyle = ("Arial", 30)
/ txcolor = white
/ itemspacing = 5%
/ showpagenumbers = false
</survey>

If you want to do the same for the instruction pages as a precaution, you can do that by adding an <instruct> element in the script:

<instruct>
/ finishlabel = "Press SPACE for next page"
/ nextlabel = "Press SPACE for next page"
/ prevlabel = "Press BACKSPACE for previous page"
</instruct>