Curious compile error, easily fixed

[Rich Shepard]

Attempting to compile a document using pdflatex halts with an error
referencing a verbatim@ environment. Since I've not explicitly used that
environment, and a search of the .lyx file doesn't find that word present, I
wonder why it suddenly decided to show up each time I use the chord, C-x h.

Regardless, when I close the error window and repeat C-x h pdflatex happily
compiles the file.

Has anyone a thought about why the error would appear if the environment
'verbatim' can't be found in the .lyx file?

Rich