How much free space do you have*? And how many photos do you have in your L1020**?
I also have an L1020 with Developer Preview, and I am also encountering crashing apps (not limited to Bing apps, but other apps as well), but they do not crash every time I try to launch them - only at certain instances.
*- Based on other threads here in the forums related to the L1020, many users report encountering problems when the free storage space goes below 3GB.
**- I'm also thinking that the number of photos might have something to do with the lags in the L1020, but I'm still testing this theory. Problems seem to appears once more than 3000 photos are saved in the phone.