on up-to-date MiKTeX installations MetaPost is broken.
The error occurs when text is output in MetaPost code,
both, using strings or btex..etex constructs. Sample
code and log file are attached.
This is MetaPost, Version 0.901 (MiKTeX 2.4) (preloaded
mem=plain 2005.6.25) 21 JUL 2005 17:41
! Missing `)' has been inserted
! This can't happen (copy).
l.3 label.urt("a", origin)
I'm broken. Please show this to someone who can fix can fix