I am getting a "#VALUE!" error with the following formula...

=INDIRECT(A43&"!M1")+(MID(CELL("filename"),SEARCH( "]",CELL("filename"))+1,255)/100)

The INDIRECT half of the formula returns "2000" from a sheet called "C.S.".

The sheet name this formula is on is "01".

I want the value to reed "2000.01".

This formula works however if I alter anything on the "C.S." I get a
"#VALUE!" error. Can you help?