That has not come up before. Have you tried reinstalling at all? There may just be something broken in Jaksta that will come good if you install it fresh to the latest version.
If the problem continues, please supply a log file. You can find it in Jaksta by going to Preferences > General > Find Log File
Not all, but many of the recordings I attempt on cam4 might work for a short while but then turn scrambled and gray like this:
Any idea why this is happening?