Fit2Disc: Wierd issue in WindowsXP SP2?

[TECK]

Hi guys,

I've done yesterday a WinXP SP2 clean install, as I do every 3-4 months. I installed AviSynth first, then copied to a folder all Fit2Disc files that were sent to me by the author.
Before, while using the exact same OS, Fit2Disc used to create automatically a .D2V file, if I tried to open a normal .VOB one, with the tool.

The first thing that hapenned, when I opened for the first time the Fit2Disc program is the classic missing .DLL error:
"Msvcr71.dll cannot be found. Reinstalling the software might solve the problem."
It popped several times until, finally, Fit2Disc opened.

Of course, nothing worked properly. I could not open anymore a .VOB file, more exacly the .D2V file was not created anymore automatically.
Anyone knows what is the reason?
Fixing the .DLL error was easy, I simply dropped the Msvcr71.dll file into the /system32 folder.
Even then, the program does not create automatically the .D2V file, like in the past.
I get this error, when I try to open a .VOB file (both, video and audio display info posted below):
"DirectShowSource: couldn't open file D:\..folders..\VTS_01_1.VOB: An invalid media type was specified."

Sure, I have a way around this bug. I simply open DGIndex and create a .D2V file... but it's not the right way.
I'm sure I had some program installed who added all the missing/needed files, that made Fit2Disc to work well.
What I need to do to make it open automatically, like before? Do I need to install a visual library?

So far, I have the following programs installed into the PC:
Avisynth 2.55 (installer)
Fit2Disc 1.2.6
Dvd Shrink 3.2.0.15 (installer)
Dvd Decrypter 3.5.4.0 (installer)
CinemaCraft Encoder 2.70 (installer)
DGDecode 1.30
DoPulldown 1.0.0.0 (installer)

The rest is still factory WinXP, untouched.
Thanks for taking the time to read this post, I need your technical support.

[TECK]

The error is in line 2 of the temp .AVS script:
(C:\Program Files\Fit2Disc\~TmpSrc.avs, line 2)

Here it is the temp script:
SetMemoryMax(16)
DirectShowSource("D:\NATIONAL_TREASURE\VIDEO_TS\VTS_01_1.VOB")
ConvertToRGB24()

[EDIT] (I was sleeping :o)
Now, DirectShowSource() function uses Microsoft's DirectShow codec.
So I said, maybe because I did not installed any codecs, I have this issue.
After installing Sonic MPEG bundle (http://www.sonic.com/products/cineplayer/dvdmp3bundle.asp), I got a picture, but it was really broken while playing, not smooth like it used to be.
Then I realized one simple thing: the famous Avisynth trio was missing from the plugin directory... DGDecode.dll, MPEG2Dec3.dll and MPEGDecoder.dll files.

That did the trick. I hope someone will learn from my mistakes.
Thanks guys.