An issue with Lustre 2.1.1 (haven't tested other versions) is causing execve to fail with ETXTBUSY.
There appear to be two keys to reproducing the problem:
1) The file must not be writable
2) touch the file
Here's a simple reproducer that break under lustre 2.1 on hype:
$ touch foo # create it the first time
$ chmod a-w,u+x foo
$ touch foo
-bash: ./foo: Text file busy
It doesn't matter if the file has real contents or not to reproduce the problem.
NOTE: I haven't been able to reproduce this on my VM in a single node configuration. I only see this on our test cluster.