Well i can might help but gonna need some info from u.
What version of qpst are u using.
How are u going bout trying to write the prl to ur phone as in are u doing the boot write or are u using anycut from the app market to make the phone stay in diag mode so u dont have to keep booting?
im on xp but i havent seen that qpst dont work with win 7 so let me know with that and if u dont have anycut i recommend getting anycut from app market along with alogcat i think is name also.
Edit: here is how u use alogcat
new easy mthod for obtaining MSL code:
Download and install aLogcat (free) from the Android Market.
Run aLogcat and set it to filter for "sec_code"
Go to your Phone apk and dial ##33284#
When prompted for the MSL, type 000000.
Now, go to aLogcat. And it should have found a "sec_code:" line with your MSL code at the end of it. It's 6 digits.
then just download anycut and go to ur home screen and add a shortcut and select activity then scroll down to Select COM port mode. U will then have a short cut on home screen, select that and then put it in diag mode, and u wont have to do the hard boot write method and after ur done with all that u should be able to get qpst to read ur phone and write the prl, there is a guide on this site somewhere how to do it exactly so u should be good, ima kinda busy at the moment but if u cant find the default guide for writing the prl ill try to find it for u but its on this site somewhere, hope this help some what, good luck.
EDIT: i found the guide but some of the methods dont work no more like the webpage to get ur msl but here is the full guide, just happened to see it when i backed up a page lol, and here is another guide with actual pics of program incase u have trouble so here is link for that ----> http://forum.xda-developers.com/showthread.php?t=1162091
here ya go.
Motorola Triumph USB cable- Others may work but this cable was designed for use with the phone, use it if possible.
Stock Phone Driver- Found on the phone when connected via USB. This driver should be installed before attempting any modifications.
QPST 2.7 Build 366- This is what I use, other versions may work as well.
Sprint PRL 01115- This is the latest version of the Sprint PRL and includes the most recently added towers. Using another carriers PRL might eventually allow the Triumph to be used on another carrier if you can get the ESN added to that carriers database, but that's another issue that I'll leave for someone else to test down the road. Just use the Sprint PRL.
MotoConnect- Not technically required but makes the detection process easier due to notification windows.
NOTE: Phone does not need to be rooted to complete this guide.
HOW TO SWAP YOUR PRL:
First things first, make sure you have the required software and drivers installed and that they appear to be working correctly.
Now its time to get your MSL. Thanks goes to mmarz over at XDA for originally discovering this method.
1. Log into your Virgin Mobile account.
2. Click this link.
3. Although you get a 404 error page, search the page for "msl:"
4. The six numbers after msl: are your MSL code. Write them down.
Now that you have your MSL I suggest you put it into a notepad document and save it.
The next step is to identify what COM ports your particular computer uses to connect with the Triumph. Open your device manager on your computer and expand the “Ports” section. Make sure your phone has USB debugging enabled.
1. Install Anycut from the android market (it's free)
2. Open Anycut and select "New Shortcut"
3. Now click Activity
4. Scroll down the list of activities until you see "Select COM Port Mode" and click it. Just hit ok to accept the default name
5. You will see a "shortcut created" notification. Go back to your homescreen and look for the new shortcut
6. Once you click the new shortcut you'll see three radio buttons. Simply change from Mass Storage to Diag and your debugging port will be on all the time.
When changed to diag, your phone will reconnect to the PC and drivers will install if necessary. Once its up and assuming all drivers took fine, in device manager look under “ports” and look for diagnostic android interface (or something like that). The other port is the modem port and not needed in this guide.
Now that we have our COM port identified, its time to start up QPST. With QPST open, open your ports tab and click “Add New Port”. Select the port you just identified. Once added, select “service programming” from one of the drop down menus on the top bar of QPST.
Now click “Read From Phone” in QPST. You will be prompted for your MSL code which you should be able to copy and paste (or just type in) to gain access to edit your phone.
Now that you have access, open the “Roam” tab in QPST. Near the bottom you will see an option to write a new PRL from a file. This is where the PRL file you downloaded earlier comes in. Make sure you have unzipped the file, then browse to it from QPST and select it. Once selected, click “write to phone” and your phone will reboot. When the phone is back up, verify the new PRL. If everything checks out then you are done, congratulations!
Now go back into the anycut shortcut you created and move the radio button BACK to “mass storage” from “diagnostics.”
Now you are all set!
Credit to Armstrom and digi7al ph0enix