Default [Q] Lg optimus L7 ii app install trouble

Hello, guys, i have a problem: i'm unable to install some large apps (>2-4-6Mb), phone answer - not enough memory, but memory is available:

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adb shell -> df:

root@android:/ # df
Filesystem                 Size         Used         Free    Blksize
/dev                    309.56M       64.00K      309.50M       4096
/mnt/asec               309.56M        0.00K      309.56M       4096
/mnt/obb                309.56M        0.00K      309.56M       4096
/system                   1.17G      901.03M      293.96M       4096
/data                     1.78G        1.33G      459.00M       4096
/cache                  295.52M        5.13M      290.38M       4096
/persist                 11.85M        4.94M        6.91M       4096
/persist-lg               7.91M        4.13M        3.78M       4096
/mpt                     15.79M       13.35M        2.43M       4096
/cust                    29.57M        4.09M       25.47M       4096
/storage/sdcard0          1.78G        1.33G      459.00M       4096
/storage/external_SD      7.39G        7.08G      320.12M      32768
/mnt/secure/asec          7.39G        7.08G      320.12M      32768
/mnt/asec/com.dssoft.yapreader-1      4.01M        2.39M        1.62M       4096
/mnt/asec/     14.05M       12.19M        1.87M       4096

I'm tried adb install, but:

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adb install Titanium+Backup_6.1.5.4.apk 
4549 KB/s (6537384 bytes in 1.403s)
        pkg: /data/local/tmp/Titanium+Backup_6.1.5.4.apk
Can anyone help with this?

Ps. Sorry for my bad english.