求大神指教：protel DXP2004 PCB设计中怎样检查出不同网络间是否短路

求大神指教：protel DXP2004 PCB设计中怎样检查出不同网络间是否短路。另：Protel Design System Design Rule Check
PCB File : \ALTIUM2004_EAXAMPLE\28335底板0520重新布局\replace_ep3c25.PcbDoc
Date     : 2015/5/21
Time     : 8:24:18
Processing Rule : Hole Size Constraint (Min=0mil) (Max=1000mil) (All)
Rule Violations :0
Processing Rule : Height Constraint (Min=0mil) (Max=1000mil) (Prefered=500mil) (All)
Rule Violations :0
Processing Rule : Width Constraint (Min=5mil) (Max=100mil) (Preferred=10mil) (All)
Rule Violations :0
Processing Rule : Clearance Constraint (Gap=5mil) (All),(All)
Rule Violations :0
Processing Rule : Broken-Net Constraint ( (All) )
Rule Violations :0
Processing Rule : Short-Circuit Constraint (Allowed=Yes) (All),(All)
Rule Violations :0

Violations Detected : 15
Time Elapsed        : 00:00:02
是什么错误