While exporting from the pre 2.3 assignment Ive got this error approximately 1 in 6 times I did an export to a portfolio.

Coding error detected, it must be fixed by a programmer: The theme has already been set up for this page ready for output. Therefore, you can no longer change the theme, or anything that might affect what the current theme is, for example, the course.

More information about this error

Debug info: Stack trace when the theme was set up: <ul style="text-align: left"><li>line 637 of /lib/pagelib.php: call to moodle_page->initialise_theme_and_output()</li><li>line 729 of /lib/pagelib.php: call to moodle_page->magic_get_theme()</li><li>line 115 of /filter/emoticon/filter.php: call to moodle_page->__get()</li><li>line 60 of /filter/emoticon/filter.php: call to filter_emoticon->replace_emoticons()</li><li>line 157 of /lib/filterlib.php: call to filter_emoticon->filter()</li><li>line 195 of /lib/filterlib.php: call to filter_manager->apply_filter_chain()</li><li>line 296 of /lib/filterlib.php: call to filter_manager->filter_text()</li><li>line 1130 of /lib/weblib.php: call to performance_measuring_filter_manager->filter_text()</li><li>line 125 of /mod/assignment/lib.php: call to format_text()</li><li>line 39 of /mod/assignment/type/upload/assignment.class.php: call to assignment_base->assignment_base()</li><li>line 79 of /mod/assignment/locallib.php: call to assignment_upload->assignment_upload()</li><li>line 188 of /portfolio/add.php: call to assignment_portfolio_caller->load_data()</li></ul>
Error code: codingerror
Stack trace:
line 1741 of /lib/pagelib.php: coding_exception thrown
line 869 of /lib/pagelib.php: call to moodle_page->ensure_theme_not_set()
line 942 of /lib/pagelib.php: call to moodle_page->set_course()
line 572 of /lib/portfolio/caller.php: call to moodle_page->set_cm()
line 1141 of /lib/portfoliolib.php: call to portfolio_module_caller_base->set_context()
line 194 of /portfolio/add.php: call to portfolio_export_pagesetup()