Error "Resulting file is empty"

[Wang Xiangqi]

I am trying to compile a presentation file in lyx with beamer. It works  
great previously, but failed now. the error report is printed as:  
"Resulting file is empty. The operation resulted in an empty file". I am  
trying to search in the maillist, but cannot get what I want. Anyone could  
help me on it? Appreciate it.
(:( sorry for my poor English)

More thanks.