Hello Egil,
Egil Andreas Vartdal schrieb:
References created when natbib is not enabled gives correct output in the form of [1], [2], etc. and the corresponding Reference list in the text. However, since I want to have the references in the form of ie Guttormsen(2004) etc. I try to enable natbib in Insert -> layout -> bibliography. When I try converting the document to DVI now, several errors occur. [...]
I think you just have to change the used BibTeX-style from "plain" to "plainnat". This can be done in the dialog which occurs when clicking on the bibliography-button in LyX.
HTH, (og ha det godt) Dominik.-