Originally Posted by
scott.wilcox
By default, there are 2 hatch patttern files, ACAD.PAT and ACADISO.PAT.
If the drawing's MEASUREMENT variable is set to 0, AutoCAD read the ACAD.PAT hatch pattern file. If the drawing's MEASUREMENT variable is set to 1, AutoCAD reads the ACADISO.PAT hatch pattern file. It sounds like one of these does not have the hatch definitions you mentioned.
A simple test is to check your MEASUREMENT variable value and change it (from 1 to 0 or 0 to 1). My guess it is set to 1 (metric, ACADISO.PAT) and the gravel hatch is in the 0 setting (imperial, ACAD.PAT).