python3, 116 bytes

Result

AC

Duration

606ms

Code [DL]

c=list(input())
for i in range(len(c)):
	if 49<ord(c[i+1])<58:print(c[i]*int(c[i+1]))
	elif 58<ord(c[i]):print(c[i])

stdin

a5w8m3f7v9f8y4f2t2bx4dokl2h8uwp2jn7i4h3v4q2x4kc7b5n5g3z3k6d7j2h2r4ns2t6t9u4zg7p2o5ve4vb6

stdout

aaaaa
wwwwwwww
mmm
fffffff
vvvvvvvvv
ffffffff
yyyy
ff
tt
b
xxxx
d
o
k
ll
hhhhhhhh
u
w
pp
j
nnnnnnn
iiii
hhh
vvvv
qq
xxxx
k
ccccccc
bbbbb
nnnnn
ggg
zzz
kkkkkk
ddddddd
jj
hh
rrrr
n
ss
tttttt
ttttttttt
uuuu
z
ggggggg
pp
ooooo
v
eeee
v
bbbbbb

stderr

Traceback (most recent call last):
  File "/volume/CODE", line 3, in <module>
    if 49<ord(c[i+1])<58:print(c[i]*int(c[i+1]))
IndexError: list index out of range

strace