Emacs hint that: Cannot have two processes for the same document

Question

I have installed emacs 24.2, okular 0.14(with KDE 4.8) and Texlive 2011 in windows7.

I want to use okular to view pdf file generated by latex in emacs.

Hence I have configured okular in my .emacs as following:

(setq TeX-command-list
         '(("TeX" "tex --src \"\\nonstopmode\\input %t\""
            TeX-run-TeX nil t)
           ("LaTeX" "%l --src \"\\nonstopmode\\input{%t}\""
            TeX-run-LaTeX nil t)
           ("View" "yap -1  -s %n%b %d"
            TeX-run-discard nil nil)
           ("SView" "F:/KDE/bin/okular.exe --unique %o" TeX-run-command t t)
           ("PLaTex" "pdflatex -synctex=-1 \\nonstopmode\\input{%t}"
            TeX-run-LaTeX nil t)
           ("PView" "start \"\" %s.pdf" TeX-run-command nil t)
           ("BibTeX" "bibtex %s" TeX-run-BibTeX nil nil)
           ("Index" "makeindex %s" TeX-run-command nil t)
           ))

As you can see, I want to view pdf file via okular when I using SView command. However, there have some problems with okular:

I opened a tex file named answer.tex emacs. Firstly, I use c-c c-c and PLatex to compile the file to pdf. Then I use c-c c-c and SView to open it via okular. Everything works fine until now.

And then, after I changed some content of answer.tex, I want to re-compile the file. Hence I press c-c c-c in emacs and choose PLatex to compile the file. But the emacs show a message in the minbuffer: Process SView' for documentanswer' running, kill it? (yes or no)

If I input no and Enter, then I get a error message in the minbuf: Cannot have two processes for the same document

My questions is: how to avoid this error message as I view dvi file via yap?

Any help would be appreciated!