合并pcb版时发生问题

求助！我在使用sub-drawing导入PCB版的时候（元件库已合并），发现被导入的PCB版元件序号都变成了“C?、R?、U?”，并且出现如下信息：

Clipboard Paste Session Started at Aug 14 10:11:04 2008

Component already placed.
Unable to paste the symbol - ("TII_182" "PACKAGE" "J1")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "J2"
Refdes not assigned at location X 54.19 Y 165.485
Unable to paste the symbol - ("TII_182" "PACKAGE" "J2")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "M12"
Refdes not assigned at location X 54.19 Y 190.985
Unable to paste the symbol - ("BLT_0_8_3MM_1_6MM_TOOLING" "PACKAGE" "M12")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "M3"
Refdes not assigned at location X 49.39 Y 156.485
Unable to paste the symbol - ("BLT_0_8_3MM_1_6MM_TOOLING" "PACKAGE" "M3")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "M11"
Refdes not assigned at location X 49.3454 Y 178.035
Unable to paste the symbol - ("BLT_0_8_3MM_1_6MM_TOOLING" "PACKAGE" "M11")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "D8"
Refdes not assigned at location X 49.19 Y 199.685
Unable to paste the symbol - ("SMB" "PACKAGE" "D8")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "C73"
Refdes not assigned at location X 55.7182 Y 150.4651
Unable to paste the symbol - ("CAP0603N" "PACKAGE" "C73")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "C103"
Refdes not assigned at location X 58.39 Y 156.385
Unable to paste the symbol - ("CAP0603N" "PACKAGE" "C103")
*WARNING* (axlDBCreateSymbolSkeleton): Refdes not found - "L4"
Refdes not assigned at location X 59.19 Y 162.085
Unable to paste the symbol - ("L0805" "PACKAGE" "L4")
Refdes not assigned at location X 57.29 Y 164.185
Component already placed.
Unable to paste the symbol - ("CAP0603N" "PACKAGE" "C15")....................................有很多，估计包含了所有的元件

请教大家怎么解决这个问题?被导入的那块PCB单独做DRC检测都通过了，都很正常。就是合并的时候发生了Refdes not found 的问题！急~~求教！

导入导出都要选中PRESERVE REFEDS

并且在另一块板中要将要导入的这些零件先删除。

你说的两条，第一条我做到了（但是不明白为什么LOG里面出NOT FOUND）；

第二条我不太明白具体应该怎么操作：（

我昨天第一次操作的时候转过来的PCB是有序号的，但是在合并原理图（是想合并原理图后再导入合并后的网表这样两块板子就真正并在一起了）的时候用了ORCAD的自动元件排序功能对新增加的图纸进行元件排序，然后再导入网表以后就出现了上述的问题，之后无论怎么操作，哪怕用备份原理图，备份PCB，序号都还原不到第一次导入的状态。非常头疼，不知道是什么原因引起的，单独的两块板子完全没有问题，但是一但合并就发生了这样的问题

原理图合并后导入的网表好像和导入的PCB完全没有关系一样，导入的PCB元件序号依旧为“?”，而网表中的新增元件都在PLACE里面，唯一正常的就是线还在。