The error messages are self explanatory. There are obtuse messages such as:
WARNING cosxx1=1+0.0004 reset to 1.
These indicate that the roundoff error has accumulated to the point where a calculated cosine is greater than 1 (or less than -1), which, of course, will cause the ensuing arccosine function call to choke. As long as the value following the plus sign (or minus sign) is small w.r.t. 1 you're okay. If this number is large, it indicates a serious problem in the code, which should be brought to the developers' attention.