which version of pd are you using? if you are using the msp tree, please try the devel tree ... it's just a guess, but maybe flext needs some of the threadlocks thomas introduced ...
No, flext should be ok with any PD version. Externals might need the threadlocks though....
Hmmm, rereading that, my posting is only partly correct....
Flext can deal with any newer PD version (i think 0.36 upwards) and the threaded version will use the PD sys_lock features if present. These have already been incorporated into the main PD line by Miller a while ago. Given that, please note that there is some dependency of flext and derived externals to the PD version (and the respective m_pd.h header file) they have been compiled for.
best greetings, Thomas