More info please :-)
such as LibO version, OS and version, detailed steps to reproduce, etc.

[NOT REPRODUCIBLE] with master daily build 3.7.0.0.alpha0+, Build ID: ff27d84, tinderbox Linux-Fedora15-x86_64@4-gcc-4.6-dbgutil, pull time 2012-06-25 23:42:59, on Fedora 15 x86_64 with English LOCALHELP installed.

1. open Start Center
2. press <F1>, localhelp appear
3. select tab <Find>
4. typing "search" without quotes, <Enter>
5. result appears and browse-able

Sorry,
UBUNTU 12.04 and LibO 3.6.0.0beta2 build ID:f010139
Danish help installed
US English help not installed

I will try to install English help but I'm on vacation now so it might be in couple of days from now.

(In reply to comment #2)
> UBUNTU 12.04 and LibO 3.6.0.0beta2 build ID:f010139
> Danish help installed
> US English help not installed

Still [NOT REPRODUCIBLE] with the environment described (x64).

Note that I used the packages downloaded from website, and installed in parallel. This means I didn't use ubuntu PPA. What did you use? How did you install (in parallel / normal install)?

Could you describe / explain the exact steps how to reproduce it?

> I will try to install English help but I'm on vacation now so it might be in
> couple of days from now.

If it still crashes in any help languages, please use libreoffice PPA at https://launchpad.net/~libreoffice/+archive/libreoffice-prereleases, install libreoffice-dbg, and follow http://wiki.documentfoundation.org/BugReport#How_to_get_backtrace_.28on_Linux.29

This problem may be a Java 7 problem. See bug 50371.

Hi,
I installed parallel as well using the following script:

---
#!/bin/bash

for i in LibO-Dev_3.6.0.0.beta2_Linux_x86_install-deb_en-US/DEBS/*.deb; do dpkg-deb -x $i . ; done
for i in LibO-Dev_3.6.0.0.beta2_Linux_x86_langpack-deb_da/DEBS/*.deb; do dpkg-deb -x $i . ; done
for i in LibO-Dev_3.6.0.0.beta2_Linux_x86_helppack-deb_da/DEBS/*.deb; do dpkg-deb -x $i . ; done

bash /home/leif/Skrivebord/libreoffice/opt/lodev3.6/program/soffice
---

I have made two tests:
Both with the following three packages:
"LibO_3.6.0.1_Linux_x86_helppack-deb_da"
"LibO_3.6.0.1_Linux_x86_install-deb_en-US"
"LibO_3.6.0.1_Linux_x86_langpack-deb_da"

First a regular installation with "sudo dpkg -i *.deb"
Result: No problem. Search works fine
Second a paralel installation with "for i in LibO_3.6.0.1_Linux_x86_install-deb_en-US/DEBS/*.deb; do dpkg-deb -x $i"
Result: LibreOffice closes without error or warning when I search in help.

Leif: could you clean all your LO install (with purge options) + remove ~/.config/libreoffice and test the package of your distrib or libreoffice ppa? (https://launchpad.net/~libreoffice/+archive/ppa)

*** This bug has been marked as a duplicate of bug 53337 ***

Slated as fixed in 3.6.2, confirming that it is fixed in 3.6.3 rc1.

Alex