could not load file "e:\application\keil\c51\examples\dallas\390\c\inst390"
What toolset? What version? At what point in the build do you get this? Are there any other errors and/or warnings before it? Please post the full text of the whole message - verbatim and in its entirety (you can cut-and-paste from the output window).
is "e" drive maybe a CD ROM drive? If so, they usually come up as read only to applications. Try copying it to your hard disk, right click on the file and de-select "read only" and try again.