Using lazarus svn trunk, I opened this project and compiled okay:

/docs/html/build_lcl_docs.lpi

From that folder I then ran:

./build_html.sh

The following was the result:

Writing 21374 pages...
Exception at 00000000004BEEEC: EDOMError:
EDOMError in DOMDocument.CreateElement.
321 Warnings hidden. Use --warnings to see them all.

Here is the complete output:

http://pastebin.com/p6DVNmXN
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After some testing I found the following units or their xml files currently crash fpdoc:

extctrls.pp
dynhasharray.pp

When I remove those two files I'm able to build the rest of the LCL documentation.
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