Cisco WAN :: 2801 NBAR Skype Detection Wrong

I have a Cisco 2801, IOS  12.4(24)T2 (C2801-IPBASEK9-M) on a WAN link to another 2801, which appears to be wrongly detecting our cross-site EMC replication traffic as Skype.
 
I am 100% sure that Skype isn't running on any of our PC's, yet the Skype protocol is by far the highest used out of everything. I have watched these traffic stats late at night when nobody is on the network and when the only traffic is replication, and this is the protocol which is constantly increasing.
 
If I run 'sh ip nbar port' , Skype isn't listed in the port-map. If I use ? at the end of the command, it lists Skype as option. The 'sh ip nbar protocol-discovery' show the following (among others):

FastEthernet0/1/0
Last clearing of "show ip nbar protocol-discovery" counters 6d10h
Input                    Output                            -----                    ------   Protocol                 Packet Count             Packet Count                            Byte Count               Byte Count                            5min Bit Rate (bps)      5min Bit Rate (bps)                            5min Max Bit Rate (bps)  5min Max Bit Rate (bps)   ------------------------ ------------------------ ------------------------   skype                    76133998                 146572068                            6167477623               173614718864                            0                        0                            1221000                  8973000
 
EMC have informed me that the port used for replication is 8888, but I can't see how NBAR can think this is Skype.
 
why NBAR is detecting Skype traffic?!