[AUCTeX] Error with preview-latex: can't find file `mylatex.ltx'

[Yevgeniy Makarov]

Hello,

I was trying preview-latex for the first time. When I select "Generate 
previews for document" in the menu, it shows "Type `C-c C-l' to display 
results of compilation" in the minibuffer. When I go to buffer with 
output it has the following content:

--------------------------------------------------
Running `Preview-LaTeX' on `test' with ``latex -ini "&latex" 
prv_test.ini 
"\nonstopmode\nofiles\PassOptionsToPackage{active,tightpage,auctex}{preview}\AtBeginDocument{\ifx\ifPreview\undefined\RequirePackage[displaymath,floats,graphics,textmath,sections,footnotes]{preview}[2004/11/05]\fi}\input{test.tex}"''
This is TeX, Version 3.14159 (MiKTeX 2) (INITEX)
(prv_test.ini
LaTeX2e <2000/06/01>
Babel <v3.6Z> and hyphenation patterns for english, french, german, 
ngerman, du
mylang, nohyphenation, loaded.
! I can't find file `mylatex.ltx'.
l.2 ...IEWdump\dump}\fi\input mylatex.ltx
                                          \relax
Please type another input file name:
--------------------------------------------------

When I select "Generate previews" for the second time, Emacs shows a 
dialog saying that the old process is still running and offering to kill 
it. When I say yes, it generates previews correctly.

Could you tell what is the deal with mylatex.ltx?

Thank you,

Yevgeniy