1. It seems that your error is due to the fact that your file is improperly formatted. The phylip format requires spaces after the sequence name and before the data itself. Since your file lacks the space, my guess is that the file cannot be parsed and appears to lack data, hence the "no inferred tree" error.

2. Multiple datasets can be passed to PhyML to conduct sequential analyses. The most common usage is to generate datasets and use them to estimate bootstrap support values.