I have a DVBworld-S2 usb box.When I try to scan
a DVB-S2 channel the box for modulation type is
greyed out and I cannot tell progdvb what type of modulation to scan for.
How do you fix this?

Don't have the pro version here, nor an DVB-S2 device.

But DVB-S2 modulation always effects a whole transponder frequency. This for, the entries in the transponder list control this.

To manually scan a new DVB-S2 transponder from 'search transponder' menu, switch to an S2-transponder before. This can either be done from the channel list or from an existing S2 transponder entry, even if not used before. After this, just change frequency and in case other parameters, to scan the new one.

You must set "s2" checkbox for s2.

He told he could not, because the check box was greyed out.

I also have the Dvbworld 2104 usb box, judging from the answers here there is no way to set modulation in Progdvb pro? I'm curious why the box exists, there must be a way? Also, can anyone give an idea of what "roll off" and "pilot" mean in the scan transponder screen?

Roll off is a parameter for DVB-T, guard interval as well.
Pilot - don't know. Perhaps something like tuner lock state.

Generally, such parameters and flags may also depend on the device used, as some may provide some flag signalling that others don't, or some parameters may be auto detected from one hardware / driver, on others a manual selection may be necessary. Like known from FEC on satellite. The Nexus, for example, provides full Auto-FEC over the driver, other tuners need to read that parameter from the transponder list.
With S2 modulation it may be quite similar.
Also possible, some DVB-S2 tuners still cannot be controlled on this modulation by ProgDVB, if they use an uncommon control for (de)modulation switching. Normally, FEC=9/10 should do the job, as that's always used for DVB-S2 AFAIK, but you can never know, what contro0l a manufacturer may use instead then...
Main problem, there's no general definition for satellite specific switches in BDA standards, like for DiSEqC, LNB voltage (including +1V option), skew, band switching or alike. Instead, as BDA was originally made for terrestrial, usually some options for that are interpreted differently, or even the drivers may be bypassed by proprietary tricks.
That's a common issue on most of the latest technologies (like W-LAN above 54 Mbit, for example), usually some general definitions are still missing for quite some time, always keeping up a draft state alive and continuously changing, causing many compatibility issues for customers and programmers as well...

Watched similar issues for the first time around 1990, when some Korean TV manufacturers tried to implement analogue satellite with normal TV concepts, trying to control audio IF by mis-using NTSC hue control voltage, stereo / A / B audio flags for audio bandwidth and deemphasis.
Crippled HiTech to avoid costs for new system controller programming

As ProgDVB tries to control most of the existing DVB devices at the same time, there is always a chance to run into compatibility issues for some options. I am sure, Prog does the best he can, but if lacking manufacturer support in many cases, it's pretty hard for him, to find a good solution for all hardware on the market.

As I don't have any of those DVB-S2 devices here, that's all I can tell for now.

Juergen, thanks for your in-depth reply. I hadn't thought of the possiblity of dvb-t or dvb-c cards and the grayed out drop down boxes. I have noticed several people on different forums speaking about "pilot" when referring to dvb-s2. It seems some set top boxes can tune dvb-s2 but won't do it unless pilot is turned on or off...depending on which stb is used. Thanks for the info about roll-off, no need to be concerned about it for dvb-s2.

Switching the tuner always is a driver function, which way ever it may work exactly. Nothing but data communication.

Computers won't send anything like a pilot signal - as I understand it as a TV mechanic - over PCI or USB, only pure data, as the interfaces could not transport anything else.
And even STBs only use DC voltages and I²C bus serial data or similar to their tuners.
Notabene, 22kHz would not control the tuner itself, but only external switches like used in the LNBs. If it would, I'd tend towards calling this a pilot signal, alike the 38 kHz subcarrier / MPX pilot on analogue FM stereo...

This for, the word pilot must mean something completely different. Maybe a virtual piloting flag, or some digital equivalent of a status resulting from whatever...

Perhaps Prog could tell, but his English is not much better than from a computer translator.
Though, the real meaning may be hiding behind some special Russian idiom, just being translated to English without deeper lingual understanding.
From my point of view, pilot can either stand for a discrete (single function / unique) control signal, as a pilot tone control signal, or a switch state indication, like with a pilot lamp.

Once again, I told, to not have any DVB-S2 device at hand. Therefore I've never watched this working.
Of course it's possible, to get a flag from a DVB-S2 tuner, representing the demodulator state of DVB-S or S2. This would be just another one, in addition to all the others like data synch locked, AFC good and many more. But it might also mean a control switch being addressed by some special data signal, like if bypassing the BDA model, to force a tuner switch state, that's not available from the pretty limited BDA options directly. Which way ever...

But perhaps there's some user reading this, who could explain, if this in fact does something on his hardware

From may point of view, this is exactly what places like this are good for, collecting fractions of knowledge from different people.

So, anyone, please