Errors within standard header files

I'm currently getting the following errors:

c:\program files\microsoft visual studio\vc98\include\iomanip(15) : error C2059: >syntax error : 'namespace'

c:\program files\microsoft visual studio\vc98\include\iomanip(15) : error C2334: >unexpected token(s) preceding '{'; skipping apparent function body

c:\program files\microsoft visual studio\vc98\include\math.h(36) : error C2059: syntax >error : 'string'

c:\program files\microsoft visual studio\vc98\include\math.h(36) : error C2334: unexpected >token(s) preceding '{'; skipping apparent function body

As they are all in the standard library header files, and therefore read only, I don't know how to fix it!

Any help would be great.