No more error handlers available (recursive errors?)

[H20tters]

Hi! I'm learning R using the "swirl" package, and when I open the second lesson in the regression models course, the error pops up in red text:
"Error: no more error handlers available (recursive errors?); invoking 'abort' restart
Error in readline("...") :
INTEGER() can only be applied to a 'integer', not a 'unknown type #29'
In addition: Warning message:
In readline("...") : type 29 is unimplemented in 'type2char'"

Also, after this pops up, the "environment" tab in the upper right corner begins loading and has not stopped, even after I remove objects from the list.

I'd really appreciate advice on how to fix this error as well as an explanation about what it's warning me about. Thank you!