Library problem

I have my own libraries USER_INTERFACE.LIB and INSTRUMENTS.LIB.
INSTRUMENTS.LIB uses some of the functions in USER_INTERFACE.LIB.

When compiling here is the compiler messages.
line 33: ERROR QATESTER.C : ‘INSTRUMENTS.LIB’ cannot be found.

I’ve put these libraries in LIB.DIR, only the INSTRUMENTS.LIB is having problem.
here is the actual line in my LIB.DIR

C:\DCRABBIT_9.21\LIB\MARKLIB\USER_INTERFACE.LIB
C:\DCRABBIT_9.21\LIB\MARKLIB\INSTRUMENTS.LIB

What could be the possible problem on this one?

try putting INSTRUMENTS.LIB before USER_INTERFACE.LIB in LIB.DIR