You do not need to delete the vender file if you are getting the newest APPROPRIATE file for your BlackBerry by your carrier. Below is the latest version for you 8310 from AT&T
Download it, install it to your PC, plug in device, open desktop manager, update to your device from desktop manager or loader.exe. Please do a backup first.
Software For BlackBerry® Curve (TM) 8310 smartphone
BlackBerry Handheld Software v4.5.0.152 (Multilanguage)
Package Version: 4.5.0.152
Consisting of:
* Applications: 4.5.0.110
* Software Platform: 2.7.0.90
* File name: 8310M_PBr4.5.0_rel152_PL2.7.0.90_A4.5.0.110_AT&T.e xe
* File size: 89.91MB
Note: The Software Platform and Applications version numbers can be found under Options-About screen on the handheld.
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