What kind of problems are you having, and which one are you using? I've been using Weins ever since they came out (12-15 years ago?) and have found them extremely reliable, unless you are outside in bright sunlight and not line-of-site to the power pack. Inside, no problem. Of course every once in while one transmitter goes bad, but I haven't had that happen in ages. What I like about them is they are small and light. I just bought a pair of Pocket Wizards because I am doing more flash outdoors, but they are heavier and more awkward than the Wein IRs, so I will only use them when really necessary.
Regards,
Andy Pearlman
Andy Pearlman Studio