Build process frozen

[teognost]

I have a build machine with OS=WinNT 4.0 SP6 .Vbuild version 3.5 is also installed(also VStudio 6.0).I run my builds as scheduled tasks (using LaunchPad)but sometimes I run them also manually.
I have one major problem-sometimes the build process freezes at some step -always it would be a step where it is compiled a VisC++ 6.0 project.The build remains in a stage where it appears in the output section "Compiling...." but nothing happens even if I wait hours.Right now in order to continue the build I need to stop the build and start it again (using F7) but I need to eliminate this problem.Any idea what causes this behaviour?It appears not only in case of scheduled build but also in a manual build.During the build a lot of VisC++ proj are compiled (almost 40) but the problem doesn't appear on the same step but on different step every time(right now it appears almost daily as I perform daily builds).Thanks for any help u might provide!