>I am using the following code in Click property of Combo Box
>
>lcCurDrive = ALLTRIM(Justdrive(Fullpath(Curdir())))
>lcCurDir = ALLTRIM(Curdir())
>
>SET DEFAULT TO (sDirectory)
>CreateDirectory('Backup',0)
>Targetpath='&sDirectory'+'Backup\'
>Thisform.unlockallfiles()
>Thisform.Fileselect()
>Thisform.Unitbackup()
>Thisform.circlebackup()
>Thisform.Closemonth()
>Thisform.lockallfiles()
>CHDIR ('lcCurDrive&lcCurDir')
>
>The program Was Running fine, and I was able to come Back to my parent Directory using CHDIR ('lcCurDrive&lcCurDir').
>But Suddenly My Program Started throwing error as "Invalid Path" for CHDIR ('lcCurDrive&lcCurDir').
>
>Whats the problem. Kinldy Guide.

Try

lcCurDir = fullpath(curdir())
......
cd (m.lcCurDir)

There is no need to use macros in this code.