Open the report (modi report), select all (Ctrl+A) items on the report surface, go to the Format menu option, select Mode and then select Transaparent. Then save the report. This type of black behaviour can occur when report items are set Opaque. This has happened to me before through system changes - in no way did I change this setting to cause the problem. However, setting eveything Transparent sure fixed it for me.

HTH