Not really. It is possible that the casting director is not listed because IMDB listings tend to be added at the discretion of the production company, and are notoriously selective in their details. On the other hand, this may be an indication that the CD has no wish to be identified precisely because this will encourage unsolicited applications for what may be a popular sounding project, and the lack of listing should serve as a warning that they are not interested in additional applications. If prominent cast members are already on board, it is certain that there *is* a casting director attached.
You could certainly try more investigative work to see if you can track down a lead as to who may be attached to the project. Clearly, googling any online references to the project and attempting to see if any details or suggestions are given at any point in previews, fan sites or anything of that nature is a possibility. You could attempt to work through the listings of UK casting directors, their websites etc. (I assume it is a UK project) as while there are several pages worth of them in 'Contacts', the significant CD's don't number more than about 50, and you never know, they may have listed the project on their own online website.
The quickest route to test the water is clearly to work out who the production company are, get *their* contact details (which shouldn't be difficult) and ask someone at the other end of the phoneline very politely whether they are at liberty to tell you the name of the casting director attached to the project because you were interested in submitting a CV. The worst they can do at this stage is tell you that they can't do this, or that they are not interested in unsolicited submissions - at which point, you either accept defeat, or you continue to try and find a way to track down the information. I don't think this sort of thing phrased politely can cause any trouble, not least because it is unlikely you will be talking to anyone except the secretary. Whether you can get the information you need this easily is another question.
Although it would cost you money, and you would probably have to trawl through a back issue archive on-line, PCR still maintains a fairly useful listing of who is attached to which green-lighted project, often with information derived via dedicated 'stringers'. It is a risk that you might not find the information you're looking for though. Unfortunately, I don't think PCR's offices are well enough manned that you could ring up and ask them if they would be prepared to look through back issues and track down a reference for you. But if you know the name of the project, and it is prominent, PCR will probably have carried many of the details of development from month to month in the pre-production runup, and these are all cross -referenced and indexed, so you never know - it might be worth a shot.
Finally, sometimes other actors have insider information you don't possess - at the moment, this post is non-specific - no-one is aware of which project you are talking about. If you are getting desperate, posting up details here on the CCP forums may elicit a response from someone who is more knowledgable then you are - whether because they are involved in the production, have a close contact involved or whatever.
Finally, you could just wait and see if the IMDB data changes over time - though I appreciate the more you delay, the more likely the project is to get cast.
