The exact meaning of the error depends on what PVD was doing when you got the message (ie. reading the description, the actors list, etc.). The short answer is that PVD expected something different from what it got (either from a plugin or from the database). For example, PVD may have been expecting a numeric value and got a NULL (similar to '0') instead. If the value came from the database, it's corrupt and needs to be repaired. If not, then there's likely a bug in the plugin you are using.
When you say "refresh" are you talking the movie list, the skin or are you re-importing data? Do you get the error if you go into EDIT mode and SAVE?
It could also mean that your hard-drive has a bad block or two (running a disk scan for errors would probably fix this).
Since you have multiple films with the same problem, it might be an index that's corrupt...a keyword or actor that is common to all the movies for example. The fix would be simply to delete the bad record and re-import the film(s) to re-create the data (and hoping the problem doesn't come back).
I've only seen this problem with my database when an image gets corrupted in transmission from IMDB. Hmmm, actually, I also got this error when I tried to update Game Of Thrones with the IMDB plugin...using Ivek's IMDB script(s) was the solution (series, episode, cast). If you import from IMDB and aren't using Ivek's scripts, try them before doing anything else. The IMDB plugin is unstable.
The catch-all would be to do a database repair. The only problem with that is the error might keep coming back and you'd never know why.
If you post more information (a short list of the films, with Urls) and what you do just before you get the error it would narrow the search for an exact cause...with luck it could be re-created on other systems and maybe fixed by a script update.
