These are some basic guidelines for troubleshooting issues with The Mirror's Surface Breaks. TMSB is a complex application (especially if you are using a custom configuration), so this is not a comprehensive discussion. If you get stuck, feel free to get in touch with me using the Contact form, although I can't guarantee that I'll be able to solve your problem.
Like so many other pieces of technology, if you encounter a minor error (such as a single failed image out of a set), the first thing you should try doing is rerunning the processing of that set after the rest of the images are generated. If you are using any of the configurations included with TMSB, images that were created successfully the first time will not be generated again, so the processing of the one or two that failed should take place immediately.
If no images out of a set are generated, you should verify that in the Execution tab, the Script Processor Path is set to a valid location of davinci.bat from the DaVinci's Shadow script processor. By default, it is located in the DaVinci sub-directory of wherever you unzipped TMSB to. As mentioned earlier in the instructions, the first time you use TMSB on a particular computer you will need to hit the Browse button next to the Script Processor Path, then immediately hit the Open button. This requirement will be removed in a future release.
Another good general-purpose troubleshooting option in the GUI version is to reset to the default execution options (Tools -> Reset Execution Options To Default).
Make sure you have applied the latest patch (for example, 1.2.2 instead of just 1.2). 1.2.2 in particular reduces the memory used for certain processing methods dramatically.
If you are using some of the more complex processing, you may run into limitations related to the amount of memory that that DaVinci's Shadow script processor can address (2GB in the current version), if your source images are of very high resolution. With the 1.2.2 patch, the maximum size of image that can be processed for luminance/colour variations is about 13 megapixels (for example, source images of 5500 x 2360 or 5000 x 2600 in size). The limitation for statistical variations is similar, although involves the number of source bands as well. The limit for less exotic image types has not been determined, but is much higher.
This section refers to these options using their names in the GUI. The same options are available in the command-line interface. See the list at the bottom of the TMSB Tutorial 1: Basic Use article.
All of these options are located within the Execution tab.