There may not be a solution to this, but perhaps a workaround. For very large databases, there could potentially be problems when trying to read it all into a report. You may be able to break it into 2 or more portions (eg customers A-M, then N-Z, for example).

Cross-tab reports usually use a little more memory than standard reports, due to the formatting that has to be done. It could be possible to restructure the report as standard, and use formulas to get the cross-tab 'effect'. Eg "If location = 'A' then Qty on Hand else 0" for an item qty by location report, then subtotal all fields and hide the details.