LyX ⇒ Bibliography causes Error about undefined Control Sequence

[bitacovir]

Hi.

My problem is when I insert a BibTeX generated Bibliography in my document, I can't generate a PDF with the document. An error message is shown saying this.

Code: Select all

Undefined control sequence.

\begin{btSect}{test}
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

When I try with a new document everything is fine. It is only with my current document.