As those messages suggest, it's been taking too long to collect the data from the modem. The actual point in the process where the timeout time is passed can vary, so you get slightly different messages.
The most probable causes are either poor communication between the PC running DSLstats and the modem (using a WiFi link for example) or the modem is misbehaving in some way. That second cause may be because the modem has been running for a long time and has run out of internal memory, or something like that; a reboot should fix this sort of problem.