In recent version of sr_feuser_register adding custom fields with classic procedure give a TCA_INPUT marker error like ###TCA_INPUT_MYCUSTOMFIELD### in front end.
There is a commented line 61 in class.tx_srfeuserregister_tca.php
// $TSFE->includeTCA(); takes too much memory
Of course you can uncomment that line, but it takes too much memory, so instead use the complete input code:
<input id=”tx-srfeuserregister-pi1-myNewFieldName” type=”text” size=”40” maxlength=”50” title=”###TOOLTIP_MYNEWFIELDNAME###” name=”FE[fe_users][myNewFieldName]” class=”tx-srfeuserregister-pi1-text” />
Like written in the wiki wiki.typo3.org…sr_feuser_register