If we receive an error PEP packet, don't treat it as incoming PEP event

src/chat_control.py

@@ -1816,8 +1816,7 @@ class ChatControl(ChatControlBase):
 		if not hide_buttonbar_entries and _('Not in Roster') in contact.groups:
 			add_to_roster_menuitem.show()
 
-		# If we don't have resource, we can't do file transfer
-		# in transports, contact holds our info we need to disable it too
+		# check if it's possible to send a file
 		if gajim.capscache.is_supported(contact, NS_FILE):
 			send_file_menuitem.set_sensitive(True)
 		else:

src/common/connection_handlers.py

@@ -1616,7 +1616,8 @@ class ConnectionHandlers(ConnectionVcard, ConnectionBytestream, ConnectionDisco,
 
 		# check if the message is pubsub#event
 		if msg.getTag('event') is not None:
-			self._pubsubEventCB(con, msg)
+			if msg.getTag('error') is None:
+				self._pubsubEventCB(con, msg)
 			return
 
 		# check if the message is a XEP-0070 confirmation request