What are some potential solutions to resolve the '100 sampling' error?

Several solutions exist: 1) Reduce the sampling fraction in the problematic strata. 2) If the stratum is very small, consider collapsing it with another stratum. 3) Adjust the weights to ensure the sum of weights within each stratum does not exceed the population size (this requires careful consideration of the implications for your estimates). 4) If the error is due to data entry errors in population sizes or weights, correct those errors. 5) Consider using a different sampling design if PPS is not appropriate for your data.