You can have multiple instanced blocks, the nets are defined at the top-level, just like any other multi-instanced block. The internal (reuse) block schematic names are the same, they will be resolved into the connection at the top level. Take a simple example of a reuse block with 1 pin named A. It is instantiated twice and connected to nets IN1 and IN2. During packaging and layout net A in the reuse block is flattened to IN1 in the first instance and IN2 in the second instance.
I used to do it with DxD 2005, but I cant do it with 9.5.
While creating netlist, I get an error about block refdes and I dont understand it as the block should not have a refdes.
in 2005 I defined a refdes prefix so the components in the 2 blocks got the same refdes No with 2 different prefix like R A25 and R B25.
I cant do it with 9.5
You need to set the options for RefDes renumber and prefix/suffix. But this is assuming you are using the Xpedition integrated flow (based on this thread's location). Please review the on-line documentation for assistance.