I think most users have had this happen to them at one time or another so dont be disheartened Jagster.
What have you tried so far in terms or ports you use and whether they are forwarded in your router etc ?
Is the problem one thats occuring all the time or at intervals ?
I do advise you use the most up to date version of WinMx (3.54b4) simply because it has some protections not found in older versions, tbh it wont matter much atm due to the current cessation of network attacks so its your choice really, also have you popped by one of the chat rooms and asked someone to upload from you directly as this is the best way to get feedback on potential error messages that might not be seen on your end.
