The point about "tar" rings some bells. A previous version (not mine) had a pretty broken tar file. I thought that has been fixed but it could well still be the root of the problem as once you unzip and untar the dist file some of the filenames are longer than 100. There are a number of tickets on the subject including rt://50669. If I could find someone with a solaris machine, I could see if I could reproduce the issue. Also the dist action of Module::Build can override the gzip and tar but I cannot see how to hard code it in the Build.PL file.