[R] Error: STRING_ELT() can only be applied to a 'character vector', not a 'builtin'

I have a daily job that attaches hundreds of pseudo-packages containing data as promise objects (DDP's, ref: g.data package), and plots the results to a multi-page pdf device. Sometimes it fails. Under R-2.2.1 it just gave segfaults. Under R-2.3.1 it gave this error message: *** caught

Re: [R] Error: STRING_ELT() can only be applied to a 'character vector', not a 'builtin'

I suspect you have a protection problem. The specific message you quote indicates that STRING_ELT is being called on an object of inappropriate type: but it is quite likely that it is being called on uninitialized memory as the intended object has been garbage-collected. Messages from a