This may mean
[בקשה לעיכוב הליכים ליועץ משפטי [לממשלה
Application to the Attorney General for delay of proceedings.

The motion/request itself is pretty commom, as explained here:
http://www.lawontheweb.co.il/דוגמה-לבקשה-לעיכוב-הליכים-פלילי...
or here:
http://www.justice.gov.il/Units/YoezMespati/HanchayotNew/Sev...

Using יו"מ as abbreviation for יועץ משפטי is really uncommon,
but it's quite plausible -

If you look at the suggested abbreviations here, http://www.kizur.co.il/search_word.php?abbr=משפטי&searchby=m...
you will find a multitude of options, like
יועמ"ש, יוהמ"ש, יומ"ש, יועצ"מ, יועה"מ, יוע"מ
and finally also - יוה"מ
which is practically what is used in you text.