Scenarist gives error that i do not understand

[xBozx]

Currently i am trying to copy a DVD-9 to a DVD-5 using the big 3 (DoItFast4U!, DoCCE4U!, and Reauthorist) and Scenarist and have run into a problem i cannot solve for myself.
DoCCE does its work and i "Author" it (in ReAuthorist) to create my *.ecl and *.scp files (just as the appropriate guide here on Doom9 says). I open ReAuthorist.scp in Scenarist the way the guide tells me and it creates the project. Everything seems to be ok under the data and track editor tabs etc so i got to the layout tab and go to step 3, check the box and press start. This is where my problem is: about half way through the process I get an error: "Layout Failed (see message window)"
The message window (the build log) says the following:
.
..
...

Info Multiplexing
Info Multiplexing VOB Main Stream
Error Size of Vob file "C:\lotr\Scenarist Stuff\mux_data\lotr.scn-VTS_01_PGC_01_t.vob" mismatch. Please contact technical support.
Error MuxFromDB:MuxVTS failed
Error Multiplex failed
Error DVD files could not be created

Was wondering if i could get some clues as to what i may have done wrong. Is it a scenarist problem or something i have done before it?
Thanks

[influenza]

Never seen the error. Try to delete the scenarist cache and also the mux dirs in your destination directory and recompile.

[xBozx]

thanks for the advice Influenza. It seems to have worked this time around :) , but I still dont know what went wrong in the first place.