The error messages returned by ImageGlue look a bit frightening but are incredibly useful. They contain all the information you are ever likely to need to diagnose a problem. Let's take a look at a sample error message

A QuickTime error occurred indicating that the compressed data contained inconsistencies (-8969).

Draw Data: Data={308 bytes, 0x002a4949 0x00007804 ...} Type={E:\Bill\faxes\2000-02-18\1033-p01.tif} Parameters={Fit=True VAlign=middle HAlign=middle} Canvas={Width=290 Height=0 Depth=32 Buffer=0} Unable to draw file.

Every error message divides into two parts - a description of the error that occurred and a description of the environment in which it occurred. These two parts are always separated by two linefeed characters so that you can separate them out if you need to.

The error description "A QuickTime error occurred indicating that the compressed data contained inconsistencies (-8969)." is self explanatory. The number at the end is the internal error number which may be useful if you are a system level programmer. So it appears here that we were asked to draw a corrupt file.

The environment describes the command that caused the error to be raised. The operation being performed was "Draw Data" and there was 308 bytes of data passed to it of which the first eight bytes are displayed. The type of image being drawn appears to be a TIFF and a number of other parameters were passed into the function. The Canvas being drawn upon has a width and a depth of 32 bits (i.e. true color) but does not currently have a height and no drawing space has yet been allocated for it (the buffer is zero).

A TIFF file of 300 bytes would be fairly unusual so again we can assume that the file has been corrupted in some way.