ERROR : L6449E
While processing <filename>: <message>
why this error came & how to resolve this
Is the library format compatible with the Keil tool set? Was it generated with the Keil tools. Using a ".a" library is not a normal thing when Using Keil. It is more appropriate when using gnu tools.
My guess is to resolve this issue you will want to build your library with the Keil tool set.
You've already asked this question - and got, essentially, the same answer:
http://www.keil.com/forum/64222