NuSOAP look for any problems and errors
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I've a function to connect to a webservice and collect data. (with `NuSOAP` and `WSDL`)

My function should return false if any errors or problems occurred.

Which function(s) can returns errors?
(I've tried `getError()` and `fault`, but when the `WSDL` url is incorrect, first one returns `false` and the second one is `NULL`. Also when anything is OK, they returns same)