Just updated to 6.x-1.4, and started getting this error message. After reverting to 1.3, the error goes away.
Can you updatet to the -dev branch and let me know if you are still encountering this error? The function was renamed in the D7 branch, it's possible something got misplaced. Also, in the future it would be useful to know the full error message (it probably contained a file and line number that would help me track it down).
Please re-open this issue if the problem still exists for the dev version.
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